I am gathering information for my cars possible tuning and the inlet and exhaust manifolds porting seems to be a recurring topic at several forums.
Unfortunately I have not found any one yet which lists the pros and cons regarding this upgrade; just the usual opinions like "better airflow" or "better spool" and so on.

Does anyone here have experience with them or know some answers for the questions bellow ?

- Is it more of a Stage3 (300bhp+) or higher upgrade or even a Stage2 (~260bhp) car can benefit greatly from it ?
- How is the Torque and BHP curve affected by this ?
- How is the Turbo Spool affected by this ?