Let me add some additional information. If you quote any of this elsewhere, please respect this as original information and kindly provide attribution and a link back to this thread or you will be hunted down like the dog you are
Do not copy this post in its entirety to other forums or publishings please
The new car is not an RSR on license plates and is not meant to be the new RS, and not meant to be a successor to the glorious RS 3.8
In reality the 4.0 project is meant to be a "good bye" edition to the 997 GT car era, based on an RS second gen. It still is an RS second gen., only with an "enriched RS flavor" by using parts of the 2RS and engine mods using the gained experience with the 4 Litre racemill.
The very difficult engineering part was to get full 500 hp out of the engine and still keep it street legal........upping the displacement to 4 Liters would have only yielded 470 to 475 hp.
The rest was hard engineering work: Crankshaft from RSR and Cup R (not derived, same part!), modified titanium rods, new intake manifold, heads with different cr than the RS 3.8, new airbox, new airfilter, less restrictive catalyst w. 300 cells, reinforced clutch, reinforced cam adjusters, reinforced chain tensioner, complete new ECU program and the list goes on. Result is an street legal normally aspirated engine with an honest 125 hp/l.
That means 83 hp per cylinder.....compare that with any of the competition....durability is absolutely not affected, the engine is a tough as nails and will last, its really bulletproof.
Throttle response is razor sharp, rev up dynamics better than ever despite the longer stroke, low end bite from 2000rpm on.
Weight is 1360 kgs or even a little less, topped off with all fluids in the lightest spec. Lightweight bits from the 2RS but painted as gelcoat adds weight. Gear ratios same as RS 3.8
A pure Motorsports project, not influenced by marketing department. A new, less obtrusive look was sought hence the white and painted carbon bits. Very clean, almost innocent but still very racy and not aggressive.
Huge fenders, RSR exhaust, etc etc equals a car that would never see the light of day as it could not be made street legal. Already difficult to make the GT cars fully street legal in USA.