Move engine harness NB
 

I couldn't find any information on this. How hard is it to move the ECU from under the drivers side of the dash to behind the glove box on an NB 99/00? It's really in a bad spot to get to and would be so much easier behind the glove box. It looks like it's plenty long enough to reach.

Get a Boomslang and splice on that...

There's a major junction (probably 30 wires) up to the right of the instrument cluster that might make it hard to stretch to the pax side. I have an NB 01 and I removed the engine harness and ECU for my swap.

It could probably be done but the dash will need to be removed which isn't that hard with a spare set of hands.