Things to do after (very) long term X5 storage
 

I am about to see if my 3.0 will come back to life after 2 years of sitting in a garage, a minor engine refresh, and new headers.

This is a list of other things that I am thinking need to be done before I try to drive it on an actual road. Most of these are for any car, but feel free to add any E53-specific things that need to be addressed. It has been on a battery tender.

Questions:

Do I need to do gear oil after 2 years of sitting inside? Same for the fluid in the manual trans. It's RP synthetic, if that matters.
Should I clear ECU adaptations or not for a first test run?

Planned:

Power bleed the brakes
Bleed the clutch
New gas
Change oil
New blue BMW coolant (needs anyway after new water pump)

Beyond this is TLDR country
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The things that happened during the engine refresh:
Vanos seals
Disa gasket
new air pump hose
new main chain tensioner spring
new main belt tensioner and pulleys
Headers, studs, nuts, gaskets
Air pump gasket

I'm burning in the headers on the old oxygen sensors, and I'll change the upstream 02s after a few hundred miles.
Coolant system was overhauled right before I stored it, but I'll check the condition of hoses.

2 years is pretty short compared to the lengths I have seen cars sit and still start up perfectly. Battery will be the biggest concern. Either buy a new one, or try a trickle charge and see if it holds. Do a visual of belts, pump the brakes and check for feel, check engine oil, check for leaks, make sure parking brake releases, and start her up!

I basically agree ^^^ - 2 years is not very long.

The gear oil is definitely OK.

Engine oil should be changed soon, but I would actually not do it before first startup. Any acid issues are already present, and running the engine will allow things to clean / circulate, making the oil change more beneficial.

Gasoline probably not so good. But then again, might be OK. Depends how much is in there and how hard it is to get rid of the old stuff.

Battery is hopefully good. Make sure fully charged, and even with the trickle charger it may have issues.

If it were me, I would just pull the DME relay, and crank the engine a little to circulate oil with the RPMs low. After that, put the DME back in and fire it up. Then drive it around carefully. Then change engine oil, and whatever else you feel like doing.