Trip Computer Swap

[325eXTATIC]

Hey all, got an odd question for you. The trip computer in my 86 325e is on the blink, and when I bought the car it came with a complete dash panel from an 86 325i (or other higher model 3 series) as an extra part. The trip computer for that panel is significantly more in depth, and the slot in the panel is exactly the same between the two models, but when doing some work behind the dash the other day, I noticed that the wiring harness is significantly different between the two computers... Normally that would be a road block... I don't like stopping for road blocks.
Obviously there is a lot more information feeding the upgraded computer, does the Eta have a means of sending that info? How much of a pain in the a** would it be to make the upgrade. I know I would have to strip the harness and some wiring from a higher model car, is it worth it?

Thanks all

Josh