most of the higher performance pipes such as Rockets, CPI, Shearer, are gonna either be VERY close to hitting something or ARE going to hit something.. Those pipes are WAY bigger than the average pipe, and there just simply isnt enough room in the banshee frame.
If you dont like your pipes rubbing on your frame or head a lil, buy some Toomeys. BUT if you want something that will pump out about 10 more ponnies, buy one of the three I listed above.