Having just picked up my new 172 on 1st Sept 2003, I was eager to get a new exhaust to make it stand out from the crowd. I set out to buy a twin 3" Magnex. I know a number of members have this particular exhaust with no problems. I rang Demon-Tweeks spoke to the exhaust guy who said it wasnt compatible with a mark 2 as the exhaust is in 2 sections. The alternative he said was to take a saw to the existing one!! I dont fancy doing that as the motor is obviously new & if the garage got funny about the warranty, I could always pop the old one back on. The alternative for me is a K2 K-tec, but at £328 It seems a lot of money. Having said that, it really looks the part although am concerned about whether it is too noisy & will piss the neighbours off.