If you're just swapping the muffler (and keeping the stock pipe) the stock resonator will be fine. But, if you're getting a complete catback with bigger pipes, then yes, the longer the res, the better it sounds. But, I've heard bad things about cherry bombs and cheap glass packs. If you are replacing the stock res, replace it with something made from stainless steel (instead of aluminized steel), so it doesn't rust out in 6 months.