Generally you should not pay more than $500 over invoice for just about any non-high-demand car like an RS. I paid $300 over for my 2000 when I bought it from the dealer.
They were funny, I said "$600 over invoice" first and then she came back and said "How about $900 over?" and I said "$300 MORE? No, go back and tell him now I will pay $300 over. Would you like to negotiate some more?" She was confused, but he came back and I told him I was being generous with $600 but they were being greedy and if they wanted to sell the car right now it was $300 or I was going to drive to the next dealer and pick one up.
SOLD! :lol: