Challenger 1 , basic production mdoel
Challenger 1 mk2, Armour kits tested, Chobham side, Reactive front lower, long range fuel tanks(rear)
Challenger 1 mk3 (op.Granby, 1991), Added new radios, all round chobham armour on the lower hull, ive heard that troop leader vehicles had GPS fitted.
Challenger 2, new turret, gun, powerplant, tracks, basically the C1 hull shell with a refit.
Challenger 2 mk2 (Op Telic 2003) using the armour packs from the C1, extra skirting on lower side armour (urban anti mine and FOD), replaced the gunners GPMG AA mount with a normal pintle mount
Challenger 2E, export model fitted with lower grade gunnery system, ,50 cal mountings, no armour add ons.