Looks like doing the thermostat is an easy decision based on all the input. I would personally get the BMW indy to do that and install/register the battery. If they can do the updates as well, great. Ask how much it is of course, but my guess is that it will be close to the price of a parts store (for the same battery). If the price is close, give them the business. You want them to be there next time you have a problem. Plus you'll have one stop service and loose your car for the least amount of time. All while endearing yourself to your new mechanic. (IMHO)
'07 650i Coupe - Black Sapphire Metallic
M6 bumpers, skirts & wheels
BMW M Cross Spoke Composite 101 Rims 20"
HUD, Comfort Access