I was told that Lexus approves of the 215/60 and 215/65 tires for the 15 inch wheels as an upgrade from the 205/65. I have owned lots of brands over the years, and I wanted to upgrade the tires that came on the car, so I searched tirerack.com and found that Bridgestone had a good rating, superior to the Michelin MXV-4 I was considering. Costco had the 215/60-15 RE930i on sale, and I bought them. I am very pleased with the handling, ride and looks. They are slightly noisy, a bit of a whine at highway speeds, but otherwise I have no complaints. I think the most recent version of the tire is the RE950. They were also $230 less for a set of four than the Michelins. Worth a look anyways.
By the way, that is a truly excellent colour on your car - must be a beautiful car.