rabbit pu

I am working on a 81 pu it had 1.6 gas cis injection. i am going to try and put a 1.6 electronic fi. i know i will have to change the wiring harness under hood and under dash also dash. it is coming out of a 86 golf. see any future problems i will run into. i have evry thing out of both auto's it will fit i think. please reply if you ever done this before