Integrale from wrexham lent me his challenger to try on my carrera track i have had no problems at all ,challenger learned the track which is quite intricate and proceeded to turn in consistant lap times up to now it has desloted only about 4 times after the fastest part of the circuit which I have put down to the tyres picking up a bit of debris ,a quick clean and problem solved . In slow mode it never faults but its just too slow to make a competitive race , but in fast mode if I use one of my slower cars it is intresting .