Drivers side air spring (at 169K), although this was due to a fault in the self leveling rear suspension pumping car up to max height, then the weakest link in the chain goes. £140 for the new part.
Rusted connection rods on passenger side self leveling sensor, causing false ride height readings.
Rusted lower lip of tailgate (a problem I've seen on a few other 5 series estates of this age)
Rust in sills. Ratchet on handbrake lever broken.
Various sensors telling me there's faults, eg ABS and ASC sensors tell the dash there's a fault every so often.
Car once would not go into 1st 2nd or 3rd gear, after about 10 minutes of playing around with gear lever problem disappeared, never to return (18 months so far!).
Despite a few problems with sensors etc, which are to be expected on a 12 year old car with so many sensors, the car has been absolutely great.
The 2.5 straight six may not be a firecracker, but it is very smooth and refined, gives around 35-40mpg on an easy run, low to mid 20's around town.
Not that quick off the mark, but the car weighs around 1700Kg, is very solid and picks up well over 3000rpm.
Comfortable, spacious, green leather interior with aircon etc, very relaxed motorway cruiser.
I'd love another one, great cars, just watch the rear suspension on touring models though!