[superek4]

All the cars are designed for race, that's why are pro kits.

X1 CRT has a bigger spur 62, whereas x2 CRT is 48. Internal gear ratio is different, x2 CRT diff is spiral, x2 CRT chassis is narrower n longer, all electronics n engine moved towards the center, x2 CRT has 16mm big bore shocks.

It's not worth it to upgrade x1 to x2 I made that mistake before, the chassis, universal, big bore, gears will cost u like a used x2 CRT.