Autosport Connectors

On my project which is a 1985 911 the wiring loom runs from the ECU (under left hand front seat) outside the car, along the floorpan and up into the engine bay, this will make it incredibly difficult to install/remove in 1 piece, so I was looking at an autosport connector in the engine bay

As I have 70 odd wires I think I will need a 100 way version and have to split some of the power across 2 contacts which I guess you would do under the boot at the connector? it seems this may be a better way than running 2 wires all the way.

For the EGT probes I will need the correct pins, which I believe are incredibly expensive? I cant find any info on these at all.

Is there a more cost effective (cheap) tool to crimp the size 22 contacts than the DMC?

Also open to ideas as this adds a big chunk to the cost of a loom that only needs to be club spec.

Consider using more than one connector. I will sometimes use a 6-pin connector with larger pins for power (fuel pumps, fans, coils) and grounds.

Can you put your EGT amplifier(s) on the engine side of the firewall?

As you identified, you can do a lot of splicing on the firewall side, and run a single wire for things like 5V sensor supply.

I would say if you're going to use Autosport, then the cost of doing that includes the tooling you need. You could sell the tools when you're done. But unless this is the last harnes you'll be making, consider it an investment. Compare it to the cost of tires for your 911 (or a tank of race fuel) -- you replace those regularly, but a tool could last you a lifetime !

PS. Have you considered putting the ECU in the engine compartment? A 911 stays relatively cool there.