so i bought this 03 cobra and it came with a roush side exhaust and skirts on it. problem is, it sounds like a whoopie cusion when i really get on the throttle. the car sat in the guys garage covered up for a while. it only had 3300 miles on it. is it possible that the mufflers or cats are messed up somehow? im also being told that i should put in a shorty bbk pipe with cats to eliminate 2 and he also said hed like to cut out the roush mufflers and weld in 2 magnaflow bullet-shaped mufflers. the other problem i have is im left with 2 holes in the back. can someone fabricate a couple things to fit in the slots?