yes port and polish done correctly will definitely improve performance...
price depending on who is doing it... there is no fixed price for port and polish job...
u can try nastyportflow in usj 1, behind summit.... they have some high precision tools there.... its not like u can try n error when it cmoes to pnp ur car.....
If you in jb can try xh racing,call0197853245.
I did my 6a12 v6 pnp together with 3angle and skim head at xh racing ,jb.price affordable.definately increase hp but need to adjust valve timing.
How many Kits are there in the market?Pls Share if u have information.I can only share you with what i have and taken out from my car.HKS GT-SS Power produce is 320Hp on engine with standard internals and 0.6bar.HKS...