Some info I just found:

An absolutely exceptional and beautiful example of this original southern California rare, coveted and extremely collectable completely stock 1991 GMC Syclone AWD pickup with it's original matching # 4.3L turbocharged V6 engine with only 35K original and babied miles - obviously never abused! No history of any accidents and absolutely no rust whatsoever! Imagine what this 3500 pound truck drive likes - how about better than when Porsche builds a car with an intercooled turbocharger and four wheel drive! This truck must be seen to be believed and driven to be fully appreciated - the engine is as new, unbelievably responsive with excellent oil pressure and no oil leaks and which sounds absolutely magnificent, the 4 speed TH700 R4 (same as found in the Corvette) transmission shifts smoothly through the gears and the engine temperature always remains cool. #2,503 of only 2,995 Syclone trucks produced by GM in 1991! If you are unfamiliar with these beasts, go to www.google.com or www.youtube.com and check out "GMC Syclone" and see for yourself how this truck achieved the distinction of being the quickest and fastest truck ever produced - an absolute wonder of engineering that produces 0-60 in under 4.6 seconds and a top speed of over 160MPH and burns up Ferrari's (see Car and Driver magazine - in 1/4 miles test the Syclone beat a Ferrari 348TS and at the Bandimere Speedway near Emich, Colorado the Syclone beat a Ferrari Testarossa with a 385 HP 12 cylinder engine in two 1/4 mile tests hands down!), alos will rip Corvette ZR-1's and Porsche Turbo's with ease!! Weighing only 3500 pounds, the Syclone was the first production truck to receive a 4 wheel anti-lock braking system and featured sport modifications and a lowered beefed up suspension and full time AWD which help keep the Syclone planted on the pavement meaning that these fastest production trucks in the world handle pretty good too! The Syclone has a liquid-cooled intercooler and although unconfirmed the club support sites rate the engine's actual horsepower at around 330HP. Capable of 0-60 in 4.6 seconds (Stock!!) and a quarter mile run in 13.4 seconds at 98 mph. 2,995 models were produced in 1991 and were only available in black.