I would imagine pulling the dash out of the way and doing the drilling from the inside would be easier. I've seen pix of the process from the firewall side in. It looks like a bitch from there.
This will be the biggest undertaking i've ever done on a 240sx. I've pulled v8's and done engine rebuilds but this will be a first for me as far as harness swaps and such, so i do appreciate your input Kruked.
-Royce