www.tyremen.co.uk of Hull have a good reputation and the painted Alutec wheels they supply are TUV approved with a five year warranty (never buy polished and lacquered alloys because they cannot resist winter road grit and salt).

Yes, the base model IS300h comes on 16-inch wheels with 205/55R16 tyres which put a lot more cushion between the rims and the road. Unfortunately you still need to "disclose" the "modification" to your insurer.