One tire on my E430 is busted (G'Year Eagle F1 GS-D2; 235/45-17) - nail right where the sidewall meets the contact patch. It's definitely not repairable, according to local G'Year pals. I plan to get a replacement today. The others have 17K on them. Of course, it's better to get two, but can I get away with just replacing the bad tire, continue my normal rotation pattern and duration and hope all will be fine?