Rynof6 seems to have the right idea about offsets. But as offset ratios change with the rim width getting the right information is vital to getting the best fit. I'll guess that a good tyre fitter could measure the offsets to get the fit right on. I hope. Might need to do offline research then post it when I can get figures. I'm still keen on finding a 20" version of the standard XR6T rims, like the company that made the 20" versions of the Dark Argents, including the different widths. Has that stock but somethings different look. These would do, once you change the centre cap, but only come in 9" for the Magnum and 9.5" and 10.5" for the BMW Apec E70's. No idea of offsets on them though. But if those fit....