I guess the factory 4wd lt wt might be a referance point. Looks like it came in at about 2400 lbs w the special 4wd system.
Found the following statements:
"Steering was power assisted, as on the stock Carrera 4, the braking system getting dual master cylinders with an adjustable balance bar for fine-tuning the bias. Underneath, a thin coat of Cosmoline was sprayed on for rust proofing. Very little was done to what was effectively the stock RS engine, but with no muffler or catalytic converter, these cars were probably realizing close to 300bhp. The motor was coupled to a Rally gearbox similar to the type used on Porsche’s old Paris-Dakar contenders. It featured two switches on the centre console that allowed the driver to adjust the torque split of the centre and rear differentials. Meanwhile, the body shell was hopped-up with sliding Plexiglas side windows, aluminum doors, an aluminum front lid and an engine cover fabricated in fiberglass.
A fixed spoiler similar to the type used on the 911 SC/RS was installed along with faired wing mirrors and retaining pins for the front lid and engine cover. In the cockpit, no carpeting or soundproofing was applied, Porsche equipping each of these factory hot rods with an aluminum roll cage, racing seats, a small three-spoke steering wheel and Halon fire system. Tipping the scales at precisely 1100kg, the Carrera 4 Lightweight’s extremely short gearing meant it was typically good for around 130mph and 0-60mph in under 4.5 seconds. Just 20 were built, all of which are believed to have been finished in left-hand dive and painted Grand Prix White."
Found a couple of interesting pics.
Note dual non bosted master cylinders:
Note mufflers:
Oil door:
