I have a 2004 WRX and a friend of mine recently replaced his exhaust with Scooby Sport exhaust. I was wondering if it would be worth it to take the old stock up pipe and down pipe and hollow them out. I can not afford a new exhaust system for my car right now and was looking for a way to upgrade the exhaust. Is doing this worth it or a waste of time. His car was a 2002 or maybe a 2003, is there a difference in the exhaust? Please help. At least I wouldn't be ripping apart my stock exhaust to try this idea.