Hi mate, I have a 3.0i and did the DISA valve rebuild recently. I believe there is a good kit available in your country and it should take about an hour. If you Google BMW DISA you should find stuff about how it fails and how to remove and rebuild it. I'd do the DISA ASAP as it's easy and cheap and can avoid an engine failure. I'm also assuming 3.0i not si by the way.
Aside from the springs, which hasn't affected me (yet) front trailing arm bushes can wear which causes a bit of wandering steering. You can feel this under heavy braking, it feels a bit like the front wheels shift back slightly when you hit the brakes. I think people do this themselves but I had it done and it didn't cost too much.
I guess your roof motor is okay but keep the drain holes clear to stop water getting into the motor housing. I just had my roof motor done and it's not cheap!