Originally Posted by Padgett

I just went through this with my new long distance tourer. Came with 18x8.5 front with 235x50R18s and 18x9 rear with 265x45R18 rear. Since not a track car I went to 17x8s on all four with 235x60R17s all around. Did require spacers/tuner lug nuts with extended shanks to clear the calipers. Drives just fine and has a noticeably smoother ride while tires are about a Benjamin less each than the 265s.
As long as nothing rubs and you do not get any bump steer, there is no reason not to.

Living in Florida where we get intense rainstorms I value wet traction and lack of hydroplaning very highly. Mercedes has 17s that will fit nicely. Make sure they are for 12x1.5mm bolts and not 14s.

ps whole thing started because the almost new Michelin Pilot MXM4s that were on it were terrible in the wet (first street Michelins I've seen that were bad in the rain). Now have BFG T/As that are excellent.