Another thing is when i go through lower gears and i get on it, i get this high pitched whiney buzzing sound that reminds me of when i made new Welds on my old exhaust with just the muffler. I was thinking this was because of the home made straight pipe with newer welds that i did myself, which are ok, but not the best. So if i hollow the cat maybe i wont get the buzzing sound because there are no welds? anyone else have this sound?