Separated by 400 pounds and 235 horsepower, the comparison of these two is quite intriguing. When the chassis are fundamentally so similar, how does a little extra girth and a different power delivery alter the performances of two racing 911s?

The environment plays a major role here. For one, the long straights of Road America obviously favor the turbocharged car, but several long corners and sections with abrupt direction changes may give the lightweight Cup car the edge. Either way, we get to see just how the purest, most focused, track-specific 911s vary depending on their form of induction. We've seen a heavier GT2 RS go against the Cup, but this time the two entrants sport the same tires and more similar weights.

For the driver, one of the most experienced wranglers of 911s was called in. Leh Keen, ALMS and Rolex Champion, has won countless races in a GT3 Cup, and thanks to his Porschephile/collector father, he's hooned a 993 GT2 racing car at one point in his career, too. For the purposes of this comparison, Keen was given several exploratory laps to get to terms with both cars, then given a set of fresh slicks to try and snag the best possible times.

While Keen's steering inputs looks very similar in both cars, it's obvious that the Clubsport has the ability to spin the rears more easily and the steering post-apex is much busier. Deploying the turbocharged power in slow corners is tricky; we see when the rear steps out violently (5:31) leaving the Turn 8. That said, the Clubsport does a good job of remaining composed while sideways over the curbing. It's far from an unwieldy beast, and if the car can get pointed the right way soon enough, the grunt does help a lot towards finding the laptime.

Up until that point, the Clubsport had a several-second advantage, but through that little slide and the subsequent, long, and front end-testing Turn 9 (in which the Clubsport appears to understeer more), the lighter, looser Cup starts to claw back slightly.

However, Road America is a fast course which rewards horsepower. With several straights and a decent uphill section between there and the finish line, the turbo power makes itself felt, and Keen crosses the line 3.2 seconds earlier in the turbocharged monster. Quiet, smooth, less crucial on mid-corner momentum, and relatively encouraging to drive, the GT2 RS Clubsport may be the gentleman driver's ideal racing car.