I have a91 525 5 speed, M50 engine with almost 400 000km. The car has been almost completely maintenance free, and has been extremely reliable. Parts are also not unreasonably priced.

I'm getting to the point where I need to dump a bunch of money into the suspension - probably to the tune of about $2000. This isn't really an eappealing thing for me to do, as I really like the car, but it is wicked slow, even with my EAT chip. I am considering replacing it with a 1991 M5, as prices are very reasonable now - sub 10k - and I could most likely sell my current car to help offset the purchase cost, making it a palatable option.

The other advantage in owning an M5 would be that I would be much more willing to invest in the necessary maintenance, as it is simply a superior car.

My question is basically this: I know the M5 will require more maintenance than the 525 - but HOW much more? How much per year does it cost to run one of these cars as a daily driver? I would love to hear from current owners.