Hey Mate,
Might be a good idea to start going through here and listening to all the sound files to identify what type of sounds you like as everyone likely has a different perception of "grunt" and "cannon" sound
viewtopic.php?f=55&t=2382Other than that, what are you looking at doing?? mufflers... catback.... headers back...
custom you would have no idea how it sounded until it was mounted on the car. but in terms of cost if you were looking at good quality.. mufflers id say you should allow about $500... catback... probably around $1000 and headers back would probably be around $2000 as a rough estimate. But if you go through the exhaust page im sure you could find a mass produced exhaust you like and just import it.