Other than routine maintenance, very little. When I first got it, I hit a huge pot hole which messed up my suspension pretty bad. The dealership fixed that for me under warranty with no problems.
I love this car and I love the dealership. Northside Nissan in North Charleston, South Carolina is the place to go if you want a good deal on a new or used car. They are fast and friendly. They gave me $2,000 trade in on my previous pitiful excuse for a car (an Oldsmobile Cutlass Ciera) and it probably wasnt even worth half that much.
I don't think I'll ever get another car, but if I do, it'll be a Nissan.
I also own this car. So far the following have failed; left headlight piglet, trunk latch mechanism, and air compressor... despite these repairs I would reccomend this car to anyone. The performance is outstanding allowing me to compete (and usually beat) most cars on the road. The car mixes sports car handling with luxury car styling. And many of the features available with the GXE are not offered by even ivy league manufacturers (digital dashboard and heads up display etc)