Pulling up at the stop sign, I can hear someone shouting at me. "Dude. Hey dude. Over here man." I turn to my left and see a big guy in a 300C, daytime rap radio station blaring, leaning across and waving his cellphone camera at me. "Oh man! What is that ride? That is sick, man. Sick. Dude, speak to me!"

I would tell him, but I can't as I'm wearing a full-face helmet and don't really want to get into a conversation. Plus the lights have just changed to green, so I settle for just a nod, then leave him at the junction frantically stabbing at his cellphone as I disappear into the distance in this road-going UFO. "Dude. Dude! Wait up..."

This kind of scene is normal when you're driving the Callaway C16 Speedster, the latest and possibly greatest of Reeves Callaway's Corvette-based creations. While the world goes wild for the new supercharged Corvette ZR1, Reeves Callaway is wondering what all the fuss is about. He's been building eye-popping 200mph+ supercharged Corvettes for years.

Starting back in the early Eighties, Reeves and his crew at Callaway Engineering have been force-feeding, re-engineering and rebodying General's performance car with ever greater effect. Done more as adverts for the firm's engineering abilities than for pure kicks, the cars have set some landmark performance figures that have only just been beaten - and not by much - by the likes of the Shelby SSC.

The most outrageous of these creations, which was driven on public roads to and from the test to prove its docility, was called, simply, SledgeHammer. Building on a 231mph run achieved in an earlier project car called Top Gun, Sledgehammer was a twin-turbo 898bhp machine that hit 254.76mph - more than 100mph faster than a standard Corvette - at the Transportation Research Center in Ohio on 26 October, 1988.

If you compare that power output with the marginally slower Veyron, every one of which Bugatti claims has 'at least' 1,001bhp, it's clear that there was some pretty special aerodynamics going on to allow the less powerful Sledgehammer to reach a higher top speed. This know-how, which was christened the Aerobody, was supplied by designer Paul Deutschman.

Callaway and Deutschman have been working together ever since. Likewise, Callaway has stuck with GM since their first project together. He was working on the Alfa Romeo Callaway Twin Turbo GTV-6 when his work was spotted and, even though he's produced special Camaros, Aston Martins, Mazdas, Holdens and even Range Rovers since then, the Chevrolet Corvette has been the main focus of his own-brand Callaway Cars ever since.

Hitting fast forward through Callaway Corvette history, we arrive in the present day where there are two different types of Callaway car. There's the C15 FIA Corvette race car, which just won the 2007 manufacturer GT3 championship, and there's the road-going C16 range which comprises the coupe, the convertible, and the otherworldly Speedster you see here.