I don't own an X-Ray but here is my take on it. You will for sure need softer springs and thinner shock oil. Probably two spring rates down from the ones in the kit and a 40%-50% shock oil reductuction. A different chassis and or top deck won't be needed. I think X-Ray has standoffs that you can remove to allow more felx if you really want it. A one-way might be be helpfull. Most importantly, go to the track, practice, setup the car, compare your lap times with other people, rinse and repeat.
Team Associated TC5 - Teambr00d CO27, Futaba S9550, Novak Rooster, DSM