I'd check EBAY for some nice 18 takeoffs from someones e70 and get a set of Blizzaks or the like for winter setup. When I lived up north i always had a set of winter and summer wheels. find a set thats hub bore fits your year (can't recall if hub bore size has changed...."search" is not my friend!)...

TPMS modules changed during production years (I think 2010 - again I'm being lazy and not trying the search function here) so you'd just have to make sure the set in your second wheels was compatable. once they're mounted i think you just have to reset the sensors in I'drive...swapping between sets of 20's on mine i don't recall doing anything, they just worked.

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