I;ve always been using the hole in the firewall behind the turbo for my gauge wiring. is there another one not so close to the turbo that i can use for electrical wires?, i cant seem to find one. and also can if i drill a hole in the firewall is it illegal? it would be a 10-15mm hole.

There's another one higher up but it comes through behind the dash, so you'll be having a lot more trouble routing anything through but can be done. I think there's one on the passenger side too.

on the pasenger side theres a good one that is for the aircon/heater drip thing, its got quite alot of room as long as you dont block the drip pipe

I've used the aircon ducting one as well. has worked a treat.

yeah, i run 0awg power wire in my car just were the A/C drip pipe is on the passanger side, might need somones finger on the inside to guide it as there is a plastic bracket that the solid wires just hit into. use some lube to buddy :O)