1993 525i M50

I read a post some time ago about replacing an o-ring at the bottom of this tank?
I have to remove the coolant level sending unit as well?

To do this service, I'm assuming all I'll need (part-wise) will be an o-ring for the tank and a gasket/o-ring for the sender?
I prefer to have all my "ducks in a row" for less downtime for the car.

Thanks for your help and feel free to e-mail me directly.
Bill