Cool I just hit 110k. What I've had to change so far was the expansion tank, the radiator fan, radiator hoses, total tranny service, upper bushings (still a problem). Now the indy shop tells me my steering rack is bad(23 hundred) and I also need a valve stem job (32 hundred) bc they found a leak...yikes!!! So I'm a lil worried. I love the 550 but what next. Seems like my radiator fan comes on awful fast and the car seems to rumble at stoplights then I turn off the ac and the idle is fine. What to do beside hearing over and over that I should of bought a 535

 

Sorry to hear about all your issues! I have read that the valve seals are somewhat common in these cars. I'd suspect is because of the ridiculous 14k oil change interval. That's way too long.
Keep in mind that the 535 has issues with deposits in the valves and it's costly to get cleaned. I almost got a 535i, but didn't want to deal with that.