I just got Greddy (Trust) Axle-back for a present. Its slighty used (bout 4-5 months on a 00-Lude) I was wondering what kind of piping should i use 2.5 or 2.25 inch? I realize that if you have the piping made too big you loose the back pressure and evensually burn valves, on the other hand if you get it too small it defeats the purpose of getting cat-back installed. Any and all input is greatly appriciated, Thx

 

I think you will be fine with 2.5. It isn't that much piping so you don't need to worry about loosing too much back pressure.