Originally Posted by Suvlaki

It will affect performance but not toooo much. The bigger rim has a bigger radius, and thus the gravitational moments of the rim have been spread out futher from the source of the torque. (Approx 1".) Thus, the engine has to apply a little bit more torque to get the wheel rolling at the same acceleration as an 18" wheel. Since you'd still have the same engine, then the torque is fixed. You will, in turn, lose some acceleration.

In other words, if you want to squeeze all the performance you can get out of your Z, stick to 18s. Else, if you care more about looks, 19s will work fine.

Originally Posted by oman

Auto's = chick magnet cars