I'm thinking of getting an A6 avant so decided to hire one for a few days to see what they're like. I've got a 3 litre diesel Quattro but not sure if it's the 204 or 245 bhp model. I'm probably going to go for the biturbo but would like to know what I'm driving this weekend. It's pretty damn quick so thinking it's the 245. Is there an easy way to tell?