That means most GT3 RS 4.0s will still be on the wrong side of 3,000 pounds, but Preuninger is quick to point out the GT3 RSR — an all-out race car — isn’t much lighter. “The RSR is about eight percent lighter than the RS 4.0,” he says. “Including fuel and the 25-kilogram penalty ballast it has to carry this season, it weighs 1,245 kilograms (2,745 pounds). The dry weight for the race car includes fluids but no fuel, so if you subtract the fluids and ballast again, you end up with a dry weight of around 1170 kilograms (2,579 pounds), compared to the 1,270 kilograms (2,800 pounds) of the street car.”
Preuninger says that cost eventually imposes a limit to weight paring: “If we used carbon-fiber rear fenders and had to go through all the safety testing, the integration process in the production line, and then take quality and homologation into account, these fenders would end up costing 15,000 euros each — just to save a few kilos. So we enter an area of diminishing returns for a lot of extra cost.”
He says the RS 4.0 saves 22 pounds over the RS 3.8 with lightweight parts such as lighter coil springs, polycarbonate front fenders, Plexiglas rear side windows, carpeting that has had its backing shaved off, and rear underbody diagonal bracing struts in alloy rather than steel. As with the GT2 RS, the front luggage compartment lid is carbon fiber, but the piece is lighter on the 4.0 due to the painted finish, which is lighter than the finish coating required for flaunting smooth “bare” carbon fiber.
The recipe of low weight and high power are underlined by the RS 4.0’s outstanding acceleration. 0–62 mph takes 3.9 seconds, and 99 mph can be reached in just 7.9 seconds. 124 mph comes 11.9 seconds after leaving the line, and the car will continue on to 193 mph.
“Naturally, there was a lot of back-to-back evaluation with the 3.8, which was our benchmark,” concedes Preuninger. “As well as the expected track work, we did a lot of testing on the autobahn and normal roads in real-world conditions to see exactly the difference between the cars as the customer would perceive them.”
While the differences between the RS 4.0 and the RS 3.8 are immediately clear if you drive them back to back, they are harder to quantify if you drive them in isolation — especially if significant time has passed in between your drives. In the 4.0, the seat of your pants picks up on an extra degree of precision in the steering and chassis. Where the 3.8 handles as near perfect as you could want a street-legal 911 to, the 4.0 surprises with a fraction more grip and finesse that just gives it the edge.
The changes made in the flat six’s evolution to 4.0 liters offer slightly sharper throttle response backed up by noticeably more torque in any given situation. Where the 3.8 motor is gutsy, the 4.0 feels even more muscular. The critical (for road use) 2000–3000-rpm range is where the 4.0 is discernably better than the 3.8. When you aren’t in a big hurry, one gear higher than usual is the norm.
But the RS 3.8 is already so responsive, torquey, and rev happy — and it’s already so blindingly fast and well balanced that if you already own one and never get the chance to drive one of the 600 4.0-liter cars, you won’t be missing out. As good as the 911 GT3 RS 4.0 is, my previous conclusion still stands: I would be perfectly happy to drive an RS 3.8 — even after the applause has ended.