The 991 Turbo is about 240 pounds lighter than the Z28. The weight advantage grows even larger for the rear wheel drive GT3 which Autoweek weighed at 3,152 pounds. That is incredibly 458 pounds lighter than the 911 Turbo but a whopping 668 pounds lighter than the Camaro Z28. Despite the GT3's 3.8 liter flat-6 power disadvantage of 30 horsepower (a 3.8 liter flat-6 giving up only 30 horses to a 7.0 liter V8 is incredible in of itself) it has the better power to weight ratio of the two. It also has a quicker shifting dual clutch PDK gearbox to the Z28's traditional manual.
So how do they stack up on the roadcourse? The GT3 surprisingly is not wearing carbon ceramic brakes like the Z28 although they are an option for an additional $9200.00. It is on similar soft tires equipped with Michelin Pilot Sport Cups whereas the Camaro has Pirelli P Zero Trofeo R's although the Trofeo R's have the softer treadwear rating. The 991 GT3 has 305mm tires in back but the Camaro has 305's at all four corners. The GT3 has 245's in front.
The quicker lap around the Barber Motorsports Park goes to the GT3 although it is close. The 991 GT3 does a 1:35.76 to the Z28's 1:36.29. Roughly a half second between the two cars. Is that half second worth double the money? That is up to the buyer to judge.
The 911 GT3 is the more technologically advanced car of the two making efficient use of its engine with dual clutch technology and a low curb weight. The Z28 keeps costs down with a manual transmission and the C6 Z06 tried and true LS7 V8 (which is about 70 pounds lighter than the ZL1's supercharged LSA). It gets very close to the GT3 for half the money. Autoweek believes this is the best roadcourse car for $75k and it is difficult to disagree with that assertion.
These are both special cars and the automotive world is a better place with them in it. Hardcore track cars like these are dying out so as far as this network is concerned they are both winners and spectacular enthusiast cars.