M5s are amazing cars but i just couldnt live with the fuel bills. One of my mates has ran one for 4 years now and the fuel bills are ridiculous. Brakes are very dear and his has had 2 diffs and clutches under warranty.
Another mate has one for a short time.... hes also owned boxters, F355, F360, F430, 3 Gallardos, 1 GTR and all the usual cossies, evos etc and said the M5 was by far the worst on fuel out all those cars!!!!!