My point is, that "concept" was not made by anyone at Aston Martin, so it absolutely cannot be indicative of what Aston's Vision GT car is going to be.
Besides, they've only shown an obscure teaser sketch so far, and even then, apart from sharing the same basic proportions (as they both seem to be mid-engined) and the strake that goes through the doors, there are already some clear differences between the two. The shoulder surfacing is different; even the glasshouse is not the same as the DBC "concept". Aston Martin clearly hasn't "already showed their concept car", as you claimed.
Comparing it to the Audi R8 and Walter de Silva (it was actually Frank Lamberty's design; Walter de Silva was simply Audi's design head at the time) is therefore questionable at best.
Sorry, I just hate it when people mistake some budding designer's portfolio project as an actual car by an actual manufacturer.