dont get a cannon...they dont look pretty either. get a nice simple twin tip setup.
mine consists of a 2.5" catback with two mufflers, one dual chamber one in the center and the rear one is a straight through leading to twin tips. i had it running on just the rear muffler with a resonator in there for about 3 days and i took it back cos it sounded awesome from the outside but the DRONE in the cabin was awful. it ended up sounding pretty neat, cost me $550 all up (mind you i didnt supply any of the stuff myself, was a scratchbuild)
a highflow cat will help too. which is on my shopping list
heres a pic of mine