Went ahead and put a set on my 08 RWD, went with Falken 452s
Had the 245s and I did not like the wheel being the outer edge instead of the tire. 10 mm worked out just right to put the tire past the rim.

1 LB. more per tire but worth it for the protection of the rim.
Had Lexus throw a 4 wheel alignment on it to help out with the inside rears wear. Noticed I used up a set of rears on after finishing a 5000 mi. road trip probablly got 25K on them total so it was needed.
Pretty amazing car, we have done several road trip and cosistantly get 30+ MPG on the freeways at anywhere from 75-85 MPH. and stil have plenty of power when needed
Much better ride now. The wife and Iove this car!

 

A number of people have done this. Smart move. 4lbs of unsprung weight has zero effect on performance, but the incremental contact area will give you better cornering and protection.

I would have done this too but the size wasn't available in the Michelin PSS