(meaning it sells only Michelins) have the Pilot XGTZ4's in the 255/40ZR17 size? I've seen 255/45ZR17 but the 540i Sport's (sedan) rear tire size is 255/40ZR17. I don't really like the OE Dunlop Sport 2000's. IMO, Michelin tires are the best tires in the world. If I were to retrofit style 19 wheels in mixed width I would like to use the same exact width, profile and speed rating (Z; above 150 MPH) as the OE tires (235/45ZR17 for front and spare; 255/40ZR17 for rear). Usually, auto pros recommend using the same tire size as the factory if an accessory or aftermarket wheel is the same size as the OE wheel. Any info would be very helpful!