So I am looking to do a little bit of exhaust work on my silverado 4.8L. My buddy suggested a muffler delete and a tip, but i have heard that a muffler delete robs hp, so i was thinking a high performance muffler, how much hp would a dynomax bullet muffler give me? i would like to stay cheap so i was thinking just a single pipe, just replacing the muffler. i still have my 2 factory cats everything else is stock. i will be putting on a cold air intake soon though. any help with this would be greatly appreciated. thanks!