What they do is remote control your laptop using Logmein.com. Then when they are ready to start, they blank out your screen so that you can't see what they are doing. They obviously run a custom application that is windows based which does the reprogramming while the screen is blanked out on your end.

So they get the app onto your computer, install it, run it, update your ECU, then uninstall all traces of it, then give you back control of your laptop.

So you will need a computer that can execute windows code. A Mac running a windows emulator that is running Logmein.com can do it, I don't see why it can't.