If I want to do all that(minus the turbo part) on a 4G15, how much will it roughly cost? My engine has clocked 200k km and has never been overhauled before. Will there be any noticeable performance gain after overhaul?
Depending on where you do it - wira ranges between 3.5k to 5k thereabouts. And once you skim the head you'll definitely feel a difference.
And like what Vr2turbo said - if there's nothing wrong with the engine such as burning off oil, leaks, loud clacking noises, severe loss of power, etc.. why would you want to overhaul? Just a note though, at that kind of mileage I hope you've already changed your timing belt at least twice.
Choke? I thought choke is only available in carburetors. Maybe it is un-burnt fuel. The smell is quite hard to bear. Feels like want to vomit if I inhale it too much.
The round middle thing on the middle of exhaust piping is not cat con? Or that is a different thing?
The fuel smell has a few possibilities. Your car is running super rich for some reason. When was the last time you cleaned your TB and changed your fuel filter and charcoal canister? Have you checked your spark plugs? Are your coils running right? Are the plug cables any good?
The exhaust generally looks like this :
Extractor --> catcon --> Flexijoint / pineapple --> resonator --> muffler
But looking at the age of your car even if you had a catcon, it's probably completely worn out anyway.
Check to see if the exhaust fumes when starting the car (cold) has strong petrol fumes. If yes then your car has a problem somewhere causing it to run rich. If not, then it's possible you have a failed seal somewhere. I can't recall if the Wira had a petrol filter seal or whatever you call it, the Myvi has this issue with that seal that once broken, the petrol fumes will seep into the cabin. But for the Myvi the smell is always there, not just cold start.
Oh and what type of spark plugs you using? Too cold range perhaps?