My 2004 facelift 4.4 is on its last service light, with the next scheduled item being an oil service. So far I have a full BMW history and car is approaching 70k miles. I don't plan to change the car for a while yet. In addition to the oil service there are a few other niggles that need addressing. I'm trying to decide which work to do via BMW / Specialist / Myself!. For the following jobs, what would you guys recommend and what are the likely costs for BMW / Specialist / DIY approach? (and how difficult?)
1) Oil Service
2) Replace a non functioning central locking solenoid on the OSF door (been using the key for months now!)
3) Sort out an intermittent problem with my rear PDC sensors (occasionally, usually when it is warmer outside, my rear sensors act as though I'm up against something even though they're not. i.e. i get the continuous tone all the time. I've tried identifying the faulty sensor via the 'clicking method' but cant tell any difference between them all!)
4) Slight rumble from front suspension and mild wobble under light braking - any ideas which bush / link this is likely to be?
Thanks

G