Pretty much everything except the gearplates are interchangable. I'm pretty sure that Aurora AFX gearplates will fit XTs but not the other way around. The gearplate clamps may require some slight adjustment. The JL TJet magnets are a great upgrade for the Aurora cars, being on par with Super II magnets. I wish JL would make them and the armatures available as a service part. The XT magnets seem to be a little better than Aurora AFX/MT magnets but the difference is not as great as it is with the TJets. The R2 and R3 XT chassis are very strong runners, better than most any stock Aurora AFX/MT.