My 10-yr old German car is in the shop at a mechanic I haven't used but who comes highly recommend by a friend in the auto business. Here are the things they have told me need to be done (and that I am going to pay for because I agree they need to be done):

Replace engine ventilation valve (its been leaking and burning oil) — $2K for valve, new manifold gaskets and coolant
Replace transmission pan gasket and filter — $650
Fuel induction decarbonization — $180

The one I'm less certain about is their recommendation to replace both secondary air injection switching valves. This is listed as a recommendation based on a diagnostic code (and something the manufacturer has apparently communicated to shops about in a technical service bulletin) but isn't based on any performance problem that I've noticed. Each valve is $500 and the total job is $1,700. They say that its possible that when they pull off the valves that they might just be able to clean them and it won't require new valves (which saves $1k) but I wonder how motivated they will be to pursue that option. Any experience with these valves and thoughts about how important this repair would be? Maybe I should Google the code and see what online chatter says about it?