wait. head gasket 490?

Mine is not overhaul but just engine leaking for my 13 years old Avanza 1.5cc

Change items
1. Flywheel oil SEAL
2. Timing chain GASKET
3. Fuel pump gasket
4. Head gasket
5. Oil Pan gasket
6. Ignition coil plug
7. Plug

Labour RM700. Cheap?

but you put back buggered pistons

Use what clutch ? Kring kring ka

Hmm, weird overhaul.
Reshim on valve clearance?
Water pump? Dont gamble on this and it is bitch to replace without remove many things if the engine sit in front bay.
Belt?
Valvecover's seal?

Mileage?
Cvt transmission?
Oil change interval for engine & transmission?

there are a  malay operated garage shop in subang 2, they sell many of the rare nissan part, you can call them for used part.if you needed to find something

Recommend to replace all rubber hose and water metal pipe that located underneath the intake manifold, these things not worth to save money.
You might not find all the direct replacement hose, can get it from part dealer to find similar size and curve, cut it to fit.
All the oil seal and oring advised to replace when the engine undergoing overhaul.
Skim the flywheel if show uneven surface.
For the driveshaft boot, dont use cheap brand, recommended to replace it with seiken brand which you can find in jalan ipoh.
You are good to go.

Fuel pump gasket? Wtf
Car got petrol smell? Does recommend to replace the pump if mileage exceed 100k.
Fuel rail does have some seal can be replace to prevent vaccum leak.

Oil pan use gasket glue

P12 Sr20ve 20v use coil on plug, i doubt he actually change it which you almost impossible to find in local, unless he got manyak lubang.

NGK iridium spark with 7 hot range should good enough.

Meter has been tempered.....any reason why u bought it even though it has been tempered?
Previous owner ur friend?

I check 3 shops d all quote labour not including parts at 700.. Any cheaper shop to recommend?

You could have bought a Mercedes GLC250 with the money spent on old cars.

After overhauled, still an old metal scrap.

Recommended to send the head to machine shop for clearance adjustment instead of hand adjustment which some foreman use knife grinding stone to finish the job, no good.
Unless he manage to find genuine nissan shim to do refit.
Machine shop charge around rm20 per valve.

If the previous owner still use the original dual mass flywheel, its gotta be expensive to fix when it goes bad
If im not mistaken, the clutch plate for this 6mt is quite rare. Maybe thats the reason you rebuild it

Try ask him to usd high grade silicone gasket maker, timing chain area is prone to leak if the foreman use typical grey color stuff.
Original toyota gasket maker is quite good but expensive.

I also cant brain this. Unless he use other version of ecu with single ignition signal output.

would it cost a lot more if all engine's wear tear parts change to new one?

wouldnt you rather renew the entire engine in this occasion?  like brand sparking new....

did you change the camshafts and crankshaft?

Not valve seal but gasket maker glue, the one use on timing chain cover and oil pan.

Valve seal can get from sim ghee autopart at jalan ipoh, genuine nissan. Bring sample to them for double check, i think it is same as typical sr20

In this case, you better send your fuel injector for ultrasonic cleaning as well, you can always do a flow test first before proceed. Cleaning part must watch him do or send to reliable person to handle it, 90% in the market charge full but not doing the work properly.

Hmmm, other versions of ecu?  means not aftermarket engine management?

why would nissan equipped this engine with such type of ecu? 

how does your engine perform now in your car?  from which nissan donor model it came from?