i was in the same boat you were in earlier this year. My rear Conti's developed sidewall bubbles at about 15k miles. I was about to leave on a road trip that afternoon and needed tires IMMEDIATELY.

I was at Discount Tire, and having a small seizure after hearing prices on 19" tires, my sales guy saved my life. He said, "hey, aren't these cars basically the Mercedes roadster? I had a guy come in last week with a new one and replaced the stock tires with some high performance tires. If your cars are basically the same, wanna see if they fit?"

They were BF Goodrich 275/35 R19's. While our stock ones were only 255, they still fit, and ooooh boy did they look nice and fat. They still had the stickers on the tread. Since they were technically 'used' he couldn't sell me a road hazard warranty on them. But considering they were over $400 each brand new, I didn't mind not having a warranty since he only charged me $70 each for them. 30 minutes and $210 later, and I'm out the door to San Antonio.

Sometimes, angels come in all shapes, sizes, and uniforms. Apparently it's not uncommon for people to bring in high performance cars and get the stock tires replaced. It wouldn't hurt to ask at a place like Discount Tire. If you're desperate (like I was) that was a life-saver. And wow, I love these tires!