On the e53, the in tank thermostat came with the new tank in my case.

My radiator made it to 205,000 when a deer helped find a big leak.

On that same car the fan died maybe 190,000 but e53/m54 has a mechanical fan so it's not as critical.

That said I drove my e70 for a couple weeks without a fan after I replaced the serpentine belt; the fan is only needed if the car isn't moving and it will give you overheat warning if the fan fails and you are stopped say in a drive through. (happened to me); I just found a side street without traffic and drove a few blocks and car cooled off immediately.

It's very very easy to replace the fan, so I wouldn't preemptively replace it since it's not "mission critical". The radiator I'll wait to see what people with higher mileage say. I know more about fuel pump, disa which I think your car may have two and may need a refresh.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)