I ordered and bought my 14 Shelby for MSRP when everyone was paying mark ups. I don't know why I couldn't get a R for the same. If you order it and don't buy the dealers car you can do it too, dealers are getting adm because it's their car, not yours, If that makes sense. It's like a private party sale.
The R is VERY limited. The only people getting that car at MSRP are the heavy hitters like Leno. 99% of people will be paying heavy mark up on it. $20-30k mark up is common practice on those cars. Unfortunately.