I'm taking an motronic 1.3 m20b25 from an 89 e34 and putting it into my 85 jetronic m20b20 e30, and I'm wondering if it's any different to wire in from say if I took it from a 2.5 motronic 1.3 e30? Also any help and/or advice on how get the main body loom out of the hole in the firewall, under the fuse box, as I've got to fix a hole of rust, and don't want to weld or cut near it?