why not go for 2'?
1.7/1.8 inch hard to find, normally 2' already made...
center bullet for better respon bro, n s-flow to reduce the noise....
extractor i dunno nothing la, if use larger i think lose some power... if u see the evo3 extractor the hole is small cmpare to VR4 extractor, but maybe for turbo.. how about NA? :ph34r: