brake booster still original or have been change other models?

if you want good braking...booster convert to nissan cefiro models brake booster...that will improve stopping power.....as setting i use is slotted and cross drill disk by proride for front...rear still drum brakes.....i have done one sets of waja caliper fitted into saga knucle....but not time to install yet.....actually brake release brake release for unnesseary must avoided....use engine power instead...

did the wheels locked and tire skid? or just simply not braking and the wheels are just spinning as normal and your vehicle not slowing down as intended?

changed brake fluid? i tend to change mine very early, as soon as it's in a bit of a teh ais color and they are gone.
done brake fluid flushing/bleeding as well to ensure the system have no contaminants?

personally i find the stock braking on the iswara being rather adequate with decent performance brake pads.
anything more it's way too easy to lock the wheels and our car have no ABS - good luck if you spin out.

my brake pads to go are the EBC greenstuff
and i personally import them from UK as local distributor (pentagon) sells them at a hefty price

too sudden stop?
if require better tire grip/traction, may consider something else other than c drive2.
am using c drive 2 and to be honest it isn't really that suitable for spirited driving however for *most situations* it is adequate, decent comfort and some lower rolling resistance (LRR) also.

or, anticipate better/keep distance. or just having better "Aku brake sendiri" abs
which comes to your brake fluid, if it's contaminated (oxidized, having air pockets etc) it will respond very poorly and especially when you mentioned "faded", which may not be brake fade and it's just the calipers/servo jammed/unresponsive.

do check your caliper checked as well or get it serviced.

As for rotors, i used to have cross drilled/slotted, they eventually cracked at the drills.
Personally they don't offer that much more performance improvements over solid disc, however with just the words of "performance"/"motorsports", they are easily 3 times the pricing of normal rotor replacements just to have some drills/slots added.
They do however have less structural rigidity (due to the cross drill throughs), and no matter how tame (or aggressive) you drive they will eventually develop hairline cracks from the drilled holes. Just a matter of time/luck.
Solid discs will obviously fare better durability since it's a solid one piece, not even vents for our iswara stock rotors anyways.

comparatively, i was on IMP x drilled/slotted rotors and they were rm300+ almost rm400, while the current Shoji oem/aftermarket replacement was like rm110-150 ish iinm.
If your current stock rotors are thinned out/very old (maybe can find a mechanic can have thickness measured or just seek second/multiple opinions from various workshops), then can consider a cheap brembo(not italy ya, just cheapo china oem ones lol)/trw/shoji stock (solid disc) replacement.

i gotten my ebc greenstuff  for iswara at £46.33 (GBP) pricing.
obviously it is much more expensive than aftermarket replacements like Bosch/Bendix, like 3-5 times the price assuming they are around rm60-100 ish, but for something like brakes, i prefer not to compromise.
Not to mention i have a preference to lower brake dust pads, if that's not a requirement, can consider something cheaper like EBC ultimax (or some called black).

Yours a sedan or hatchback?

Possible source of the sound could be from the air vents which are holes in the panel to allow  suction of stale air to the outside using venturi effect. These holes bypass the door seals.

Do a test by temporarily taping up these holes and see if got any difference. After that remove the covering tapes as these holes are important for ventilation.

I am not sure, as I have not tried modifying the venting devices. I noticed that the LMST has wind noise close to the vents area and that the vents are more visible though the door gap than the Iswara. The Iswara do not have this kind of noise, so I suspect the vents are the culprit.

Regarding the swimming pool in the boot, other than the suspected windscreen seal and
boot weather seal, another culprit is the tail-lights seal. I have the same swimming pool and I did 2 things, and the results are so far so good. 

1) For the weather seal I washed off the dirt and grime and applied grease in the mating
groove to stop capillary action. (The seal do not seems to be glued, so I just pressed it in)

2) For the tail-lights I applied silicone sealant over the original seal.

Regarding the wind noise, I could be wrong regarding the vents, as there are also other 'holes' in the door (example: the opening for guide attachment between the hinges, or the drain holes at the bottom) itself that could let in noise and transmit thru the plastic trim. Need to do some detective work.....

Hunting for irritating noises has always been a pastime for many car owners ....

I have no experience in the windscreen seal, so unable to comment. Maybe sifus here can help.

I have not tried using silicone spray to stop capillary action, not sure if it will work like
oil/grease....

I have not tried using silicone spray to stop capillary action, not sure if it will work like
oil/grease....

on your feedback, could you perhaps identify if you have worn bearings or uneven tire wear? because if anything, the c drive 2 aren't loud at all unless maybe they are almost having no treads left which even then i'd still doubt on their nvh since the compound/sidewall is pretty soft.

also, metal kings. not (lol) mountain kings.

Regarding the wind noise, another possibility is the the window glass pane may not have perfect fit with the plastic guides, so there might be a gap. Just my guess only, happy hunting...

On the moisture still getting into your boot, try to look for the moisture trails, to have some clue whether it is from the windscreen seal, boot lining seal, or the tail-lights seal.

The hatchback tail-light unit is held by 3 screws, but the adhesive seal will be very strong and need to use force to separate from the bodywork.

So far my boot seal is ok, so I did not open again for regreasing. This is a lesson I learned : don't disturb the seal if it is working fine, otherwise it will start to leak again. The sealing mechanism is somehow very sensitive and many times I could not get it right.

if there is nothing wrong wit d carb, i dont really suggest to open up d carb. d last time engineer has done very well on d carb. d af ratio tuning r top notch. 4g13 n 4g15 use d same jets. its not interchangable. BUT in racing / motorsport, they do mod it wit bysharpening / make d jet more thin..

d best thing u could to is try to find unker fred n help u to tune for best performance for ur carb.

well from my C drive 2 experience on 2 cars:

195/60/15 (thick fat plain looking sidewall without rim guard)
2007 nissan sentra - treads almost completely bald, the side inner and outer already have the smaller pattern/tread exhausted, look like big block uhp tires.
still very silent
the catch: Nissan are among the best Japanese car makers when it comes to NVH

195/55/15 (lower profile with rim guard)
1999 Iswara - inner treads completely bald due to excessive camber, and that's because i "automatically" balances it out with my driving 
unfortunately that isn't the case since my sister took over and it has taken a toll on the inner treads over time.
still very silent
the catch: the leaking exhaust pretty much out noise anything on the car so...

Sentra changed to bluearth AE01 which i've provided review. (you may search for it on tire sub forum)

Iswara, well still got treads on the mid/outer, inner part too bad la lol
she supposedly drive slow and keep distance anyways, so should be ok.

if the car bang/kena bang she pay la.
she's richer than me anyways

Seems you have multiple leak locations.

The leak at the top and centre of the hatchback  boot seal : pull out the seal at
those areas, do you see moisture inside the groove and on the metal lip that goes into it? If there is, you have capillary action (water seeping and climbing via the contact surface between rubber & metal. Water is a very pesky thing, it can find its way through the nooks and crannies.). Happens even in new seals. Put some grease inside the groove and see if any improvement in the next rainstorm .

The one-finger gap : is the rubber at the gap itself wet ? Your solution might work, no harm trying. And this gap can be the source of your wind noise too?

The dep. minister's statement about the cause of accidents and cheapness of the device etc is out-of-touch with the real world situation. It will go the way of the 3 blinking speed indicator lights fixed on top of heavy vehicles many many years back.

And if implemented will mean every vehicle owner have to fork out money to some govt.
approved agency to instal...

And besides the measures you mentioned, JPJ should go undercover and catch those reckless drivers on the road. Those dangerous drivers can cause serious damage even at less than half the 110 km/hr speed, and should face very heavy penalties...

Go no faster than 110 km/h – government mulling idea of installing speed limiting devices on all vehicles
Here’s something that’ll absolutely delight all you speedsters. Bernama reports that the government is mulling with the idea of installing speed limiting devices in all vehicles, “all” being an all-encompassing term here – think along the lines of passenger cars and motorcycles, not just commercial vehicles.

The proposal – aimed at being a measure to curb the growing number of road accidents and fatalities – would see a maximum speed of 110 km/h defined by the limiter, Deputy Minister of Science, Technology and Innovation Datuk Dr Abu Bakar Mohamad Diah said.

“Limiting the speed of all vehicles is a suitable method to reduce road accidents in the country,” he said, adding that it would be in line with the law in Malaysia to set a maximum speed limit of 110 km per hour. “If this can be implemented, then we will become the first country in the world to limit vehicle speed car based on speed limits in accordance with national law,” he told reporters at an event.

Abu Bakar said that the speed limiting device was easily available, and it can be installed on all vehicles, including motorcycles and imported cars. “The device, which can limit speed as required, costs less than RM500,” he added.

He said police patrol cars, ambulances, fire engines and vehicles from other appropriate law enforcement agencies would be exempt from these regulations.

==edit==
here is the link from Bernama. 
http://www.bernama.com/bernama/v8/bm/ge/ne....php?id=1114920

personally bluearth ae01 is bad on performance.
however nvh and lrr is top notch, so really depends on what you want.

afaik there is no difference. coz it cannot interchangeable.

tuning afaik he had increase to rm70. not sure he still do tuning though. u can watapps him at 0122687273