I have a 1991 244 and a 1979 245dl, neither has cruise as an option, how hard would it be to add this?

if you get the right parts, it's not hard--at least on the '91, which is pre-wired. for this one you need the control stick, the pump, the servo, pedal valves, the computer with harness, and vacuum lines. ryan_r has the instructions on his website, but once you get all the parts, you probably will be able to figure it out yourself.

i found the hardest part was getting the servo into its place--the driver's side kick panel left too little space for it.