They are 17" rims. When I first bought the car 8-10 years ago, I replaced original brakes with upgraded and upsized rotors and calipers (Wilwood) which necessitated going to 17" rims. I haven't been to Sears Point or Laguna Seca yet, but maybe soon. I have had it at Spring Mountain, in Nevada and it felt like someone had beaten me up at the end of the day. Lots of very,very sharp turns, not exactly the Pantera's forte. Also, I don't have dropped floor pans, I have my head at a 45 degree angle with the helmet on as all of the pictures have shown. It would be hilarious, since I can't see the tach or the speedometer with my head tilted, if it weren't for the fact that at the end of the weekend I always have a stiff neck for a couple of weeks afterwards.
I have had a 2002 XKR convertible for years and just love the looks and the grand feeling. The 5.0L 2010 XKR coupe is a much different animal. First of all, the paddle shifters should come with a warning, "Very Addictive!" Secondly, it's explosively quick, especially with a gas pedal that delivers that power a little too early. My friend borrowed the XKR a couple of weeks ago to race it at Willow Springs and had a blast. He's a much more aggressive driver and goes many more times per year than I do. Buttonwillow will be a good place to get used to the XKR on the track as it's not terribly technical and therefore much more forgiving. And unlike Sonoma there are no concrete barriers staring you in the face should you run off the track!
And by the way, I think the Aston Vantage is one of the most beautiful auto designs ever made unlike the rest of the Aston Martin line which looks like beached whales. Have you driven the 5.0L XKR? It is a much different car than the 4.2L 07-09. Besides the huge bump in horsepower, stiffer suspension settings, bigger brakes, tighter steering...and the dynamic mode is somethin' else. It will be interesting to see the F-type coupe R-S with 4 wheel drive next year with about 600hp distributed to 4 wheels. It should finally catapult Jaguar into Porsche 911-Audi R-8, Ferrari territory.