We just purchased a 2006 RL with 18 inch Acura wheels that were put on by the dealer. The car has 19600 miles on it and looks like it just came off the showroom floor.The probelm is that tires are Pilot Sport AS 245 45 R18, Z rated and the ride is very rough. Any ideas on how to improve the ride? V rated tires? 17 inch wheels? I was looking at Michelin Primacy MXV4. We had those on the 2001 TL we traded in. Any help would be appreciated.