Bmw E9 with Metric Mechanics 3.7L/motronics 1.3 swap

[Ilovemy525i]

Hey all,

I have a '72 3.0cs that im doing a m30 swap on. The M30 block was modified by Metric Mechanics to 3.7L, lightened rotating mass. Im not sure if the engine started life out as a B34 or B35, however, it is setup for Motronics 1.3. The engine and tranny is mounted, just need to finish up a few details (rad, accessories, throttle linkage). However, I've run into a bit of a wiring snag, I'm having a hard time tracking down wiring diagrams for the E9 body to connect tach, speedometer, coolant temp, oil pressure, ignition signal to the engine harness.
I'm not sure where the speed sensor is/how the car reads speed. I'm guessing from the diff, do I need to worry about that for the speedometer?

I have an engine harness from a 1990 535i and a 179 red label DME. I have the pinout for the DME and traced and labeled the wires to the connector that runs into the fuse box that would normally connect to the body harness of a 535i. However, the E9's fuse box is in the dash and obviously all the connectors are different, my thought was to grab a fusebox from an e24/28/e34 (something of that era) and the round body harness connector, and effectively move the fusebox under the hood for easier access.

I would like the least amount of wiring possible to make future diagnostics a bit easier......my initial thought was to wire it up, get it running and the necessary gauges working, then move the fuse box under the hood and tidy up the e9 wiring (the 48 year old wiring has seen better days).

1) Does this sound crazy? Is there an easier way to wire the engine harness so the engine and dash will talk to each other? Presumably I can connect the power and ground of each "item" (coolant temp sensor, tach) to their respective gauge and it'll read properly.
2) Do I need to worry about wiring for a dash CEL? the E9 has no CEL in the cluster.
3) Where's a good place to find an E9 wiring diagram? im running around in circles on google and id like to avoid having to trace wires up to the dash
4) there is only one wire running from the engine harness through the connector for the tach, can I just run that direct to the tach or will I have to also run a separate ground and not use the original ground for the tach?
5) I have a miller W.A.R chip and MAF from them to handle the tuning. planning to initially going to get it running on the stock chip and then toss this one in.
6) Any advice from anyone thats done this swap/motronics 1.3 swap that might alleviate the incurring headaches
7) Anything I've missed/overlooked details?

Thanks in advance!

Update: I stumbled across this website. Seems like an excellent source.

http://e9-driven.com/Public/Library/...ges/en/61.html