i know the header thing comes up a lot but i did some searching and couldn't find what I was looking for. Can I run stright pipes off a RB road race header? I am not worried about sound or emissions. Or do I need the use presilencers?

 

You can run straight pipes. It will be very loud. I mean...VERY loud. Since you have a S5 you dont need to worry about the aux. ports opening, as long as you keep your airpump.

 

well, the RB road race is uncollected right? if you aren't worried about sound, then why would you want a presilencer?

 

so If i keep the air pump I shouldn't have any trouble thats best kind. thanks for the help

 

what size piping should i use with this set up?

 

Have a look & listen to my cheap dual setup.
It delivered good top end even with silencers & bombs.
The links are in my sig.

 

that sounds nice.. what size piping is it? I was thinking of using 2 1/4 piping. should i got bigger or smaller?

 

With full duals, 2" is fine unless you're going to be porting the motor.