86 n/a 5sp.... anyways i got my rb header friday, got it on today. sweet. now for the rest of the system. i have a single apexi n1 that i want going out the pass side. i want to put a resinator in it somewhere in between the two. so there will be no cats, but what size piping should i use? i was going to go 3" but im thinking that will be a bit too big. should i use 3" or 2.5"? whats the biggest gain. i dont care about it being loud, as long as its under 90Db.

 

Front pipe to pre-silencer - match the header outlet.
After the pre-silencer you can open it some if you want.

 

I was planning on doing rb header to a corksport exhaust which is preety mcuh like a apexi n1 and keeping the 3" in a custon mid pipe to speed up the process

 

dont you think the 3" might be too big and make a torque loss though? i need all the torque that i can get. gotta keep up the exit speeds.

 

I think that the 3 in' would be too big. I would stick with 2 1/2 in. pipes. I think it would make better torque