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Stepping up to the Rolex series means the lap times drop and the sound levels go up, as the rules are much more open. Well, that sound comment doesn’t apply to the Mazda6 GX cars, as they have the first 4-cylinder turbo diesels in the series, and are thus the quietest cars out there. The GX class allows for carbon fiber body parts, suspension and big brakes, but the class was so small that we somehow missed getting a shot of either of the two turbo-diesel Mazdas or the single Cayman.
The Grand Touring (GT) class is another hotbed for great action and fantastic cars. The rules open up significantly, and the costs go up proportionally. While the cars look like their street-going versions from the outside, they don’t necessarily have much to share under the skin. 
The Turner Motorsport M3 pictured above, for instance, houses a race-tuned version of the S62 V8 from the E39 M5. If you had to explain to someone what torque sounds like, this would be the car to demonstrate that. Note the frame rails in the engine bay which prove there’s nothing stock about the GT class.
One of the best looking GT cars was the Fall-Line R8. That’s not hard to understand after seeing what comes out of their shop, but it's one of those cars that’s just hard to stop staring at.
At the top of the Rolex food chain lies the Daytona Prototypes (DP). It’s almost a no-holds barred approach to racing, which makes it highly competitive and extremely popular. The rules that are in place, however, aren’t taken lightly. Each team has their engines taken apart and inspected by the series in order to make sure everything is within spec. As a driver, even if nowhere near this level, it’s still hard to watch sometimes without wishing you were behind the wheel. With full access to just about anywhere, however, that means you’ve got plenty of time to look at a lot of impressive hardware in the garages.
Most of the DP teams had body panels off the cars for better access, and that meant some glorious views of what goes on under all that skin. The intricacy and engineering that goes into the suspension alone is a site to behold.
