I own 1.6 Wira and mode to 1.8 before and let me tell you if you still want to stick to Auto. Upgrade to 1.8 4G93 SOHC is more better compare to modify to DOHC as Auto need a lot of torque at low RPM. DOHC is suitable for manual as the power is all at high RPM like over 3~4k rpm. Auto usually will shift gear around 2~3k rpm so you will need a lot of torque at low end to drive and shift better and the fuel economy also did not impact much compare to DOHC mod.

SOHC - Cheapest, more fuel efficient and easier to maintain drive
DOHC - Expensive and need to mode ECU to add piggyback to get the full potential. Parts are more expensive compare to SOHC and getting even rare.

Auto cars need a lot of torque at low rpm, the only mods i did in my previous 1.8 wira only direct transplant the 4G93 SOHC engine with the extractor from half-cut. The rest exhaust still maintain, if you mode to bigger pipe or take out the catalyst converter the torque delivery also will drop. Even the intake also maintain same, using original OEM filter and change every 20k mileage.

If you want to play turbo, just direct get a GSR turbo half-cut and transplant
Dont waste time & money rojak here n there, you will get a lot of headache and mechanic will be happier as you will always visit his place to fix here n there.
A lot of people never calculate the time and side effect of bolt on turbo to car. The original engine and ECU is tune to N/A, if want to modify to turbo you need to upgrade a lot of internal engine stuff & ECU/piggyback which cost a lot of money and may not be done right if the mechanic is not good in this.

If you want to stick to Auto, the best choice is just upgrade to 1.8 4G93 SOHC engine.
The gearbox can still maintain from 1.6 Auto gearbox but recommend to just upgrade or add on oil cooler for the gearbox.

This post has been edited by littlefire: Jan 25 2020, 10:56 AM

I tot you mention that your wira is already 1.6 Auto.
You want to change to manual? If want to modify also same just go buy from half-cut area.
Dont waste time & money on this also.
If you just want manual only why not just go buy a 2nd hand manual satria or Putra it is cheaper nowadays.

As per feedback before 1.6 Auto gearbox can be fit with 1.8 engine 4G93 SOHC without issue.
There is no need to upgrade the gearbox, just add an automatic oil cooler good enough.
Dont waste money bro, Auto gearbox is not cheap also.

This post has been edited by littlefire: Jan 26 2020, 06:16 PM

Good luck and may god find you a good/honest mechanic to advice you on your modification route/cost.

Still if i were you, if die die want to get for the turbo itch.
Is better to buy another ride which already done the turbo modification/transplant
Since a lot are in mudah & carlist nowadays just get your trusted mechanic to go inspect the car before purchase.
This will save more time, money and less headache for both owner & mechanic.

This post has been edited by littlefire: Jan 27 2020, 12:29 AM