Changing the barrels is a piece if cake, once you have the handles off you'd have to be an absolute fruit cake not to figure it out!! All I would say is LEAVE THE KEY IN THE BARREL when you remove it because if you don't all the little metal plates will fall out, as you will find out if you don't!! As far as the barrel pertrudging the handles, not 100% on this but I can't see them doing so, there pretty much the same handle barr the porsche logo, thats if were on about the same handles!!