I dont really know alot about pre-silencers but i am planning to put one on to increse back pressure to open up my 5th and 6th ports! But weere exactly does it go? Does it go right behind my header or does it go about half way down my exhaust pipping? I dont have any cats and its straight pipe all the way back so any help you guys have will be appreciated.

Drew

 

It bolts onto the header. I did a test on my car which is a series 5 and there was not enough back pressure to open the ports. If you have a sries 4 (86-88) you may be alright.