well first of all finally got that damned down pipe on talk about a beast half striped one of the nuts etc etc anyways got it in its the 2.5 zzp offroad conected it to the stock pipe and then in the back it meats a super 44 flowmaster. sounds really good but through some of the rpm range it has a ridiculousness amount of rasp does anyone else have a straight through setup to a exhaust pipe if so is it crazy raspy? i have heard some people talk about putting a cherry bomb in there to get rid of that acting as a resonator. if so which length should i get? thanks

To eliminate the rasp, drop a resonator back in or a standard cherry bomb muffler. https://www.gmforum.com/t281156/

what size would you recomend they have a few different ones will it make a big diff?

I wouldn't worry about length but the diameter should be at least an 1" larger than the pipe it'* connected with. So for a 3" exhaust, go with a 4" resonator. You still want hi-flow, so look for one that won't rob HP by restricting the exhaust.