Tires are almost exactly what the OEM spec is for the 17in wheel option. Not looking for huge wheels or totally stuffed wheel wells. You "should" do whatever your preference is. Also, whether or not they void the warranty or refuse whatever service you request due to a modification, the net result is the same.....I didn't get told no by the dealership but there are plenty of people on this forum who have been told they caused whatever failure they had because they used aftermarket parts.