Has the waterpump been replaced?
What did BMW replace under plan while it was still active?
Whatever was not done should give you an idea of what maintenance items are to be done.. Shocks, Waterpump, etc.
I would personally go do a Carbon Clean and Gearbox service.. The N55 motor is Solid, doubt something with the engine will go wrong.. But preventative maintenance shall be key.
100k is not a lot, that is like 6-8 months left then she is yours :=):
117k kms is a lot, she has clearly been driven well, mine is on 83k kms.