Never raced with an xray, but there are some basics everyone should follow with any brand of car.
1) Have confidence in the car you race with (can you hold THE chassis in your hand, or look at one closely and think "this car is for me
2) Keep a good supply of parts with you for race day and know of local suppliers
3) Ideally have people around you who race the same chassis for setup help
Personally, i've never had an xray as i've not liked the look of them, so the car is only worth buying if it feels right for the one using it.
It's not a car for me though...
Any top level car is going to have good results behind it, usually the only limiting factor is the reliability, and the user's racing/setting it up skill factor.
Indoors on carpet is a good starting point for on road racing, as the grip levels allow newcomers to focus more on their racing lines and car control, more than finding a setup first to find the best in the car