Last weekend I drug home a C-125 parts tractor to molest for parts for my C-161 that I got going a while back. It had all the things that the old 161 was needing: good seat, good clutch plate, better tires, and most importantly, GOOD ORIGINAL NELSON MUFFLER! Someone long ago put one of those stupid pepper pot pieces of crap on it and I nearly went deaf when I mowed with it for the first time last weekend.
Just got the muffler swapped over, and HOLY CRAP you never realize how loud something is until it's not loud anymore. What an insane difference that thing makes! I'd say at least a 40% reduction in noise. That muffler alone was worth the $100 I paid for the parts tractor.