I don't like the 55 profile tire either. The 235/55R17 only has a tread width of 9.25 inches. This is less than the current GT tire size of 245/45R17 which has a tread width of 9.65 inches.
A 255/50R17 tire would give us a tread width of 10.04 inches, the same as the 255/45R18.