The "Lux" reference is the trim pack (similar to the the S1 "Custom"), both small and large turbo cars can have this.
The large turbo cars were the homolgation specials with T34 turbo, charge-cooled / air to air intercooler, water injection and Webber ECU.
The small turbo cars have a T25 turbo, only an air to air intercooler, no water injection and Fords air flow meter based ECU (instead of MAP sensor).
The Montes can also come in both guises (small or large turbo) and consist of cloth seats with special logo, numbered plaque in banana pod, comemorative gear knob and hand-brake lever button

, external decals and special OZ wheels (as well as being limted colour choice).
The motorsport cars were basic cars (cloth trim, no sunroof, or opening rear windows) with limited weather-proofing and were designed to be bought by the rally teams for preparation (hence the basic-ness of them). They were therefore a lot cheaper than the usual cars.