It depends on your budget, there are lots of things you can do :-)
Me personally if the milage is high I would do the timing chain guides and tensioner.
May be swap out the oil pump always a good idea, melling make the pumps for bmw mini last pump I bought I got the complete pump and cover assy for about £40. http://www.ebay.co.uk/itm/Brand-New-...item1c3d06cdf7
Victor reinz make the gaskets for bmw mini
Fit a set of ARP head bolts and rod bolts and cam bolt.
Check your supercharger belt tensioner the damper fails Express car parts sell the complete assy check you idler pulleys to.
May be replace the clutch plate oem or kavs, guide tube and thrust bearing.
Change the gear box oil.
fit magnetic oil drain to the engine sump (dimple)
Check and change the super charger oil both ends
Make shore you use the correct antifreeze halfords sell it in concentrate of mixed Halfords | Comma G48 Antifreeze and Coolant RM 5L
Plenty of clean products gallons of the stuff red scotch bright
Blimey I could go on :-)
Hope this has helped and not put you off :-)