The $100 is easily worth it. Keep in mind the plastics on the AE need to be replaced more often than the Xray, so that is an added cost that most people don't factor in. In addition to more wrench time.
The quality is much better on the XRay. I raced my T4 extensively for over a year and there is minimal wear.
With that said, either car are top contenders and will not hold you back in any way. I just like a car that is better built thats all. Even the asian manufacturers (ARC, VBC) have better quality than AE these days.
Actually if I had to do it all over again, I would probably get an ARC or VBC car.