I purchased a set off ebay for $80 and didn't like them. You can see the edge of the wheel so unfortunately they look like a wheel cover up close. Also the chrome quality wasn't good especially in the the areas of the wheel crevices where it is a yellowish color. Also they will scratch your wheel rim when you remove them.
I contacted Shark Racing since their set is around $250 and they claim they cover the edge of the wheel. Plus their's bolt on. The only problem I see is if you scrape one of them up, you will have to buy another set at for $250.