A laptop with BMW diagnostic software, INPA, DIS 57, or ISTA etc. is by far your best bet but takes some time (and can be frustrating) to set up unless you can find a laptop with everything already loaded.

__________________
1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)