In my case, When I converted my XRay to short arm it turned my car into absolute rubbish. I tried everything to get the car good but even after four and a half months I still couldn't turn anywhere near the quality of laps with the short arm car as I could with the long-arm car (which I only used for a few weeks)
My opinion on the XRay FK04 on carpet (with rubber tires) is very low. The long arm car on the other hand is an absolute beast!
