I bought mine (16" stainless) ... lost one on the way back from a trip to Pennsylvania.
Now I don't know whether to buy a replacement or give up on them and try a different hubcap design.
I can't say that I've noticed a gain in MPG ... but then again, I haven't really run enough in the warm weather so I can't make a direct comparison with my hypermiling last summer.
I actually found on of these by the side of the raod ... but it was a 15"
