Does anyone know if 10J x 20 will fit on the back of a 57 plate GS 450h. I've rang loads of companies regards this question and get a different response every time. Some say there are no replacement rims available for this car because of the large calipers on the front, others say 20's fit but only 8.5J all round and a few are saying 8.5J front and 10J rear no problem with a 285 25 20 tyre. Confused.com :( any help is much appreciated. Thanks.