the 2.5 is a KV6 - shocker of an engine LOL
I sold my vitesse sport saloon for £800 recently - had 122k miles and a stainless exhaust, rebuilt gearbox and in very good condition (i actually miss the car in someways, as it was amusing to drive!).
for the mileage, i'd get the rover. i looked into a 7 series beemer a while back (4 litre v8) but went for a 3.0 v6 vauxhall omega elite but im selling that for a T5 now.. didnt want the running / servicing costs of the bmw..