I did my tranny yesterday 80k miles - uggly and some particles in the sump to boot....
will be changing again I think in another few thousand - to be sure.
8Qrts of MB fluid cost me $120.
If you're pretty handy and have a torque wrench - pretty easy - might also be worth changing the pin connector plug - they are prone to eventually leak on the 5 speed boxes. Plug cost $10 but from what I gather you only need the o-rings

Both Coolants - Supercharger +Main Engine Coolant (different)

Bleed Brakes (every 2-3yrs)

Change Engine Oil

Change Supercharger Oil (the smelly one apparently)

Engine Air Filters

Cabin Filter

I'd probably even do plugs.....and clean/check injectors + fuel rail and filter

Check both belts

I have this list - 'cause it's my list.