Seriously I'm speechless with all the negativity that surrounds when someone posts asking about bolting on turbo onto their car. Is it that bad? Maybe TS is serious about it and he just needs a point to start. Everybody have to start from somewhere.
1. many shops can do, depends on who you know
2. custom setup where got name bro, you think like japanese car can buy bolt on Greddy kit ka? That one also will cost you 5 figures
3. It's called a turbo KIT for a reason, there's definitely many things that needs to be installed.

1. Not really as long as done right the first time. Maybe just change the oil more often(instead of 7k, change at 5k)
2. depends on your foot. how much fuel you use depends on how much power you use from the engine. if you kaki binary keep boosting then your FC definitely will go down but if you just drive normal, your FC should remain the same or even better than stock.
3. 5k onwards to 5 figures depending on setup.
your concept about cars and how turbocharger system works is totally wrong. Technical experts you can refer to others who had already done it(as can be seen, there ARE turbo'd Forte's running around already), research online what others did overseas, research around BOT users from other cars as well.

- As mentioned previously, FC depends totally on your foot. You take a Golf GTi 2.0 and whack all out touge in genting and watch your fuel burnnnnn
- Usually overheating is not much of a problem, the problem about boosting high boost is whether your engine internals can take it or not. Pistons, conrods, crankshafts etc which is why you see people swapping out their pistons/conrods/crankshafts/gaskets with something stronger if they really go serious into their turbo setup. Intake manifold crack? HAHAHAHAHAHHA!! Exhaust manifold crack ada lah which is either due to shoddy welding during the fabrication of the manifold or your exhaust temps(tuning) is way too high which your pistons will melt first before your manifold will start cracking. And usually people engine blow is due to the head gasket giving way, pistons cracking, conrods or crankshaft snapping, but definitely not manifolds cracking.
- Air intake pipe cannot be straight? You gotta be kidding me. Explain why people go for ITB(Individual Throttle Bodies) then. It's basically sucking air direct from the atmosphere, no bends and whatnot. heres a video with ITB and standoff injectors.

- A properly done up car can actually get a higher RV than a normal car as long as it's properly done up. If you want you can even remove the kit and demod the car and the car will be as good as stock, plus you can earn back a few grand from selling your turbo kit.
- you know alot of technical jargons like wastegate, twin scroll and VGT but seems like you have zero clue on what those are or even means. All petrol cars running turbos requires a wastegate, be it internal or external. VGT, twin scroll are technologies which improves turbo response and performance. Since all turbo's have wastegates, do explain the relationship between wastegate and turbo lag then and also i'm curious about carbon buildup if i release throttle at the 2000rpm spectrum.

I agree that newer cars comes with new technologies that reduces turbo lag and improves performance but things that comes out from the factory isn't exactly the best. They're designed so that they can be massed produced cheaply and effectively while still able to do it's basic job, albeit not the best. Many forced induction cars(4g93T GSR engine and Preve S4PH-T are good examples) have rubber hoses as their intercooler piping which expands under boost and this expansions robs about 500rpm before full boost comes in which is why many people replace it with stainless steel versions and Samco elbow bends which won't expand under boost. Stock exhaust manifolds are also cast iron. Swapping it out with a custom-made tuned-length 'banana' manifold will increase performance as it enhances exhaust gas flow to the turbo providing faster spool-up. Long story short, not all things that comes out from the factory, designed by 'engineers' are good, there's always space for improvement.
Agree with this statement, i suggest TS to study on how turbo system works first and all the parts needed, at least it will save you face by preventing you asking stupid questions to veterans who knows their shit.
the Forte in the video is an auto and the auto GB robs alot of HP from the car. A Polo TSi may win it, but hey, it's still faster than most NA cars on the road and can easily tapao a Vios.

My 2c to TS is to do your own research and what you do is totally up to you as it's your car anyway. But before you do anyhting, make sure you have enough knowledge on hand and don't regret whatever you have done(unless you've done something really really stupid) As you can see, many of the people here in this forum are just keyboard warriors who knows jackshit about the technical aspects on cars. Long gone is the time where this forum used to discuss technical stuff like cams and engine design, now it's just a place where people compare cars and ask what car to buy with a certain budget.

long post, bye bye

edit: btw, please do NOT get your kit from Xenon. just google up their name and you'll know what i mean.