The E89 Z4 is one of the best looking cars BMW has built in many years. Is it perfect? Not quite but it is a very enjoyable car. Personally, I think the 19" wheels are a bit of a stretch especially with RFT tires combined with the roads in much of the US. There just isn't enough sidewall to resist the forces associated with hitting a pothole or obstruction. Granted 18" wheels are not going to guarantee that you won't have a problem but it helps improve your chances. Also, replacement costs are less when you do have a problem. There are a lot of good looking 18" wheels available including the BMW OEM wheels I have on my car.