the tyre placcard will save u from a defect but that's bout it... if the dimensions of ur wheels conflict the standards set out in the adr, then technically ur car is not roadworthy and any insurance company will try to make a policy void by looking out for such stuff... a mate of mine had an e36 318i with no engine mods, just bodykit, lowered and 17s... the car got vandalised on the street and when he lodged the claim, they rejected it bcos his wheels were 8" wide... even in a claim that wasn't a result from an accident was rejected bcos the was not roadworthy... duty of disclosure states that u have to mention everything to ur best knowledge, but being ignorant or feigning ignorance is not a valid excuse to insurance companies... back to the tyre placcard issue, my r33 has the orig jap placcard on the driver's side that lists the 7.5" wheel and the locally translated one in the glove box also has that so u may be able to get ur rwc...