Got Dunlops for winter and they look very streyched on stock 18 inch wheels. Installer says 245 would not make much difference and it would require sending back all four tires as 245's are a different speed rating than current front tires and he says it's not "legal" for him to install different front and rear speed rated tires. Are the 235's safe on the stock 9.5 wheels? they look real stupid.