Xray is the easiest to work on, some are close but not on the same level. The manual is top notch on the xray. If you build the xray the way the manual says, the car will treat you great. W/ xray there's no shimming, no dremmeling, no stuffing o-rings in out drives, no stuiped clips holding driveshafts on. 1 front arm and 1 front hinge pin is all I've broke in 1 year. Pettit rc has tons of set up sheets for the xb4 if your into that kind of stuff. Chop shops on ebay for spare parts.