I've been running Xray for two years and they are really great cars. The car last a really long time and the parts quality is just beyond belief! nothing fits together as perfectly as an Xray, plus the finishing on all the part is sooooooo smooth, no sharp edges anywhere, and most of the parts are so cleanly molded you cant even see the mold line. Plus Xray uses the best materials everywhere on their cars, which is why they are a bit more money. The drivetrain is really amazingly light. Oh yeah, the car drives as well as its built. The changes Xray made to the EC make it more stable and have more steering than the old TQ. Really the only problem with the Xray is that it might have to many adjustments, so if you don't know what your doing you can tune yourself right off the track.
Sorry if that sounds like a fanboy post, but I really like Xray!