I am installing a used (100K miles) engine into my 05 Cooper S Conv.

I am planning on changing the front & rear mains, clutch, water pump and rebuild the starter before reinstalling. Of course I will do oil, air filters and thermostat too. I may even change the trans oil too.

What else should I do? I heard you can change the supercharger oil.
Jon

 

Timing chain, Oil pump

 

The timing chain and oil pump only have 100K life? I figured they were designed to go longer than that.

 

This is true, but consider the amount of work to change them out later.
The engine is out, you should just get it done, remember to change the front and rear main seals.