High comp engine with turbo can perform. But cylinder head will be under stress /over heat and will not be able to sustain high boost.
So if you want to do bolt on turbo on standard engine, go easy and low boost. Stage 1 modification and get 7~10% HP out of it will do.
If you seriously wanted 20%+ then have to really change piston, valves, gasket +++ Deffy will have more to add on this list for sure.
Ong san wanted a VIP ride, he always wanted the feilo's looks only. If he is going for speed and power like me, he surely won't just stop at the VQ25 only.
Don't ask him to count FC la...his feilo is his 2nd or 3rd car. only use for feilo meeting or teh tarik at night only. I think his tank of gas evaporate faster then he can burn it.