yep i agree with white balt these cobalts should last atlest 150 or 175 without problems with it taken care of real well. also on how you drive it i kept a 69 F-250 and 91 Chevy S-10 running for years lol but throdle body easy replace and i would check or call chevy give them the vin to check...
well muffler is huge but i think the pipe is a 2.5 i just bought a new muffler to throw on for now but i think 2.5 because that is what the back part of the muffler looks.