It's obvious now you've told me!
(previous generation below)
Now I don't actually object to "original" shell designs, but I do object to claims that shells are based on cars they quite clearly have no relation to.
About the only similarity between an A4 and the R9 is the front grill shape. The lights (which are the easy way to make cars look alike) are completely different to any Audi. The rest is pure fantasy. If anything the nose is closer to the R8 supercar, the tail is like a Honda NSX, with the roofline of a Mercedes CLS.
At least the body fits the Global Body Spec. And I suppose the good news in terms of keeping touring "scale" is that it doesn't appear to handle either, everyone is still using the Mazda6.