I was wondering, does anyone know if an aftermarket exhaust, say HKS legamax, really that important if your car have a turbo? I have a friend that keeps telling me that I need other exhaust for engine to breath better air, the stock one doesn't allow the engine to suck enough air....wondering if that was true....cause from the looks on the forum everyone seems to think that an aftermarket exhaust system will do no effect for the car but making your car sounds louder

 

for FI, especially turbo, the exhaust size will matter.

3 inch piping before the y-split or a full 3 inch piping on a single will make a ton of difference if turbo'd and tuned for the rx8.

 

do you have any recommendation of exhaust for a greddy turbo? from the sound of your post you only seems to talk about the cat pipe.....but what about the catback exhaust?

 

3 inch piping before the y-split includes the connecting pipe that is after the cat (the pipe that comes with the catback exhaust). after the split it can go down to say 2.25" dual piping.

or you can go full 3 inch piping with a single exhaust. which means all the way from the cat/midpipe to just before the exhaust tips.

there are a few options. turboxs or hks hi-power are the two i can think of off the top of my head.

 

What size is the dump pipe? I'd go for 3" or more from the turbo back, if you're only doing the end section then you'd only get some minor gain and mostly that would be from a better flowing muffler/resonator than stock. Properly sized dump pipe really helps.