Yes and no. You just need a Eprom emulator. That means you just unplug your oem chip, connect emulator to eprom socket and connect emulator to your PC. Chip's data can now run by your PC and with suitable program you can change all the values (It is better to do this at the dyno) When you are satisfied with the results just burn .bin file to new eprom or eeprom. Then just remove eprom emulator from Motronic, install new chip and you're ready.
You cannot directly change the values to your oem chip while it is still in the Motronic because eproms are old technology which does not allow change the values inside the eprom. Might be easier with Eeproms, but also that would need a lot of mods to the oem hardware. It's possible with newer OBD II systems.
Check out this system designed for older Porsche Motronic's
http://www.maxhpkit.com/