Its still only about 700 odd in comparison to the 1400 odd of the e39 530d.
Is the petrol actually a runner for anyone? You would be married to it afterwards, not saying they are bad car but not many go looking for a big petrol beemer unless it has an m badge. Your dealing with reselling to a nation of people who buy warranties and don't care about the car that comes with it.
Slightly off topic there was an e60 523i in the garage for a while and it sounded fantastic, was bought for penny's and was a bit of a rare beast. I haven't seen too many around. Completely underrated but a complete alcoholic.