So what is the best Header for 500-550 hp car?

 

stock or ported stock header, in my opinion. Even if someone argues for
some aftermarket header, I believe they will not be able to document
enough power difference to warrant the amount of expenditure for it.
I would spend on opening the intake and exhaust as much as possible
first, eg: fancy new air box, S-Car-Go CF intake tracts, and a Europipe II.
Joe

 

Thanks Joe, I just put the EP II Loud on and was thinking of opening up my OEM Headers. I'm a past master with a rotary file. I found some data, misplaced it at the moment, which gave the desired port openings. Anyone have the data?

I guess the next step is a ECU Flash, DV's, Opened-Up OEM Headers, and maybe some hybrid Turbos K24/16’s.

Anyone care to speculate on the HP and torque output?

Flash-DV’s-Headers-EP II=XXX HP
Flash-DV’s-Headers-EP II-K24/K16’s=XXX HP