I’m a former IMSA racer, now Chief Instructor at Chin Motorsports the largest presenter of track days in the Southeast USA. I do a lot of track days in my MK5. If you are planning of tracking your car, I suggest that you consider 17" wheels for these related reasons: 1) running a 235X45 17, I'm putting a lot of rubber on the ground with minimal weight (as you probably know, unsprung weight is the most costly to performance)--my OZ 8.5" Alleggerita wheels weigh just over 16 lbs each; 2) the taller sidewall gives me a lot of pneumatic adjustment; the easiest at track set up change for a busy day at the track with no crew; and, finally, but not last in importance, 3) 17" tires are significantly less expensive.
