i hit FULL boost @ 2700 ish rpm (i get boost before that mark but not full until around there)
2.75 elbow
http://www.alamomotorsports.com/AMS/ams_suprao2.html
3" downpipe
http://www.alamomotorsports.com/AMS/amsex.htm
"F" the cat !
i use a striaght through 2.5 ish custom (there's your back pressure) hehehe
3" exhaust
http://www.alamomotorsports.com/prodndxman.html#Blitz
mostly using a silencer on the end of it
it sounds nice and tuned as i pull away or so i've been told .
just my 2 cents on the subject