Seconded. I have no experience of 19's but both my sets of wheels are 18 and there are no issues on the track or road. I have lowered the car 40mm at the rear and 20mm at the front (brings it level). Handling is superb and it looks sweeeeeeet!
I had instruction from one of the leaders in the GT3 championship recently and he was amazed at the cars handling and cornering speeds.
The rear is under compression slightly (this pic is at about 65mph and accelerating out of the corner) but it sits a fraction higher at rest.
