Hi all,
I have a request for a spare key to a BMW 420d, i have experience on doing eeprom work on all BMW's not had an F series yet though, am i right in thinking that there is a Cas4 unit and a FEM unit? Which one should i use to do the eeprom? What are the benefits of either?

i have Zed Full but have not yet purchased the FEM kit for it and also have VVDI Prog.

Thanks