I think, at least for the first time, it's worth getting them fitted by one of the authorised fitters in your area. Fitting may seem easy but having the right tools e.g. a hard and heavy enough soft faced hammer would appear to be a necessary implement. On the BMW (am I allowed to mention them here?) owners forum one guy mentioned that he had a hell of a job fitting them and in the end gave up and went to the authorised fitter who demonstrated that you needed a to give them quite a whack with the soft faced (his was plastic faced, not rubber) hammer. He, the BMW owner, was quite surprised at how tough the alloygators were (seemingly made of a really tough nylon, not plastic) but they were fitted after a couple of hours of chatting with the fitter and the actual work being done. Have a look at their Facebook page where there are some photos of a Porsche Cayenne's alloys saved from damage but the alloygator is well shredded. That's why they sell a single wheel kit and incidentally the silver one is in fact a grey - they can't add any metallic compounds to the nylon as it could chemically compromise the strength of the product. The air leak worry seems to be a thing of the past as the product was redesigned in 2010 and the plastic does not go far enough down between the tyre and rim to interfere with the bead of the tyre that provides the air tight seal. All this gleaned from looking and reading a lot of forums and reviews, think I'll go and see out local fitters here in Carlisle.