What are s ome commone ones I would be bound to run into with an E39 M5?

I haven't had a problem maiting since I got the M5 :o

Ive been told brakes and clutch are iffy?

We don't have too many M5 owners on this board...:(

www.M5board.com might be a better place to get some good responses.

Ive been told brakes and clutch are iffy?

they are both wear items, so will eventually need to be replaced. Depends on what you plan to do with the car. If you take it to the track, you'll need better brakes. If you take it to the drag strip, you'll need a better clutch. If you slip the clutch, it will wear fast. Several people on m5board have a ton of milage on the oe clutch, some over 100k. Others have clutches go out in 15k miles. I had my first clutch replaced at 45k miles, but it was due to a rear main oil leak. Clutch had plenty of material on it, but was oily. I later replace that clutch at 65k miles to be the dinan beta tester for their clutch. Again, clutch was fine at that time. I drive the car fairly hard, i instruct with the bmw cca and the car would see 5 or 6 track weekends per year (not that much lately though).

Otherwise, mafs fail pretty regularly, include them as an inspection 2 part and you'll be happy. There is the rare internet report of a vanos failure, or rod bearings going, but that's unusual.

Rest of it depends on the car. I'd look for something with 60k+ miles, as low milage garage queens will likely need a lot of work if they are pressed into daily service, and now there's no warranty to back you up. My car went thru a 'needy period' between 40k and 47k miles, probably got around $15k worth of warranty work, based on dealer rates at the time (around 2004). But, dealers tend to throw parts at problems, and that often doesn't fix the real problem. I've had no warranty for about 18 mos, and have had very little that the car has needed, and nothing i couldn't do myself.
Mike