I believe the answer is that these are "purpose built" race cars that have very little in common anymore with the road cars.
Likely zero parts could be exchanged.
Not like the old days (i.e. the 70's).
So even though it's called an RSR, don't confuse it with it's rear engine brethren.
If Porsche is doing this....it must be allowed per the race rules for the series that Porsche plans on running this car.
I think it's great.
It's about time Porsche got away from the rear engine platform for "all out" racing.
I think they lost a few races in recent years by using the rear engine layout.
Much more GT1, 962 and hey 914-ish now.
http://www.roadandtrack.com/car-culture/g6...sches/?slide=15