Switching the tires allowed it to pull faster lap times than a WRX and Mazdaspeed 3 here:
http://www.roadandtrack.com/special-...transformation
Edmunds did a test with new wheels which resulted in a dramatic increase in speed, plus pulling 1g on the skidpad. If you check their other track tests, you'll see that is on par with or better than some seriously impressive cars like the R8 or Panamera GTS.
http://www.edmunds.com/car-reviews/t...rack-test.html