I like aspects of the Vanquish but imho, it isn't a classic in the making in the short term... maybe in 25+ years but what would worry me is the shoddy technology in them (esp the transmission) and the cost to maintain it while you wait for it to appreciate.
My choice, given your provisos above, is to go for a run-out S4 in your specification. You know you love the car and the latest engine is great as are the myriad of minor tweeks.
