and upgraded to the 18" M-Pars. I have 16" Michelin Arctin Alpin snow tires mounted on them now and use 'em on the Touring (as my snow sled).

You never know exactly what folks have or what they've pieced together...I wonder if the ebay seller has somehow fitted the ctr hub cap from an e38 on to 15" cross spoke wheels?

There is a way to tell the size of the wheel, though...if the seller removes the ctr hub cap...the wheel size and wheel off set is in raised letters (see pic below).

This is an archived pic I had of my e38 OE 740iL spare wheel/tire...you can see that the wheel is 8 x 16 and the offset is 23mm