Personally I would only do it when you are going to a car show or a close local event.
No matter how "cool" it seems its not worth the money in parts and also taking the chance that a stupid ricer or old lady no paying attention plows into you. Thats my guy lost his 11sec convert. Someone t-boned him doing about 50 mph and completely destroyed his car. Plus cops around here aresn't to pleased with the 5in exhausts on V8s
they tend to piss off the old people