I have attached pics of the Michelin Tires. I put these tires on mostly for the ride not so much for performance. But with all that rubber how can it perform less than the hard riding run flats?
The first thing I did when I got my Corvette was to get rid of the run flat tires and so has almost everyone I met at Corvette shows who has installed after market tires. I have the BFG KD's which will probably wear out after 10K miles. The most popular tire seems to be the Michelin Pilot Sports.
I remember seeing a notice at STS that the front and rear tire diameters must be within 1/16", or .0625".
The Tire Rack has an excellent site for tire ratings including performance, ride, wet and dry weather performance, tread wear and what ever else they rate.
I hope all this info is of some help.

stock sizes?

What are you going to do if you get a flat ? Tires look Good

Later

I replaced the Goodyear EMT's with new Michelin Diamaris, 275/40R20 fronts and 315/35R20 rears. I also purchased a tire repair kit from Discount Tire Direct.

Yeah...those run flats are a pain in the ass...the freaking tire dispaly sometimes reads the tire pressure other times it reads - - and the stupid light comes on the dash... when they wear out I won't be getting run flats either.

Is it just me or do the rears not look as wide as the stock tires?

Is it just me or do the rears not look as wide as the stock tires?

Yeah Rick, they don't look like 315's. Maybe the angle of the pic?

Can you take a couple more pictures front the front and side? I want to see a couple more angles. I might join the big tire crowd