It requires drilling, but I like taking off the drivers side wheel well cover and drilling right by the factory harness pass-through. There is a very good flat spot that comes in the cabin just over the dead pedal. Really good place to run wires through and with the right grommets it is very clean.
Ok, I got it from JDH1213 up through the shifter boot. Mine had a bend in it so I slid it under the metal frame. Fills up the gap pretty well with some filler to seal it up.
I was trying to get a good picture, but it is really up in there nice and tucked away. It is the red wire next to the hood cable pass-through. Very easy and open on the other side once the wheel well cover is removed. Looks pretty neat too, IMO.
I put it in quotes to have it resized. The pic is pretty big.
If you have a big plug to pass though, you might try removing the pins from the plug and passing it through the hole before reattaching the plug. But I guess you found your route through the shifter hole.
I ran my guage wires behind the dash to the center console and to the shifter, down through a slit in the shifter boot and along the tranny tunnel. Both water temp and oil pressure.
As mentioned, shifter boot. I actually ran my direct ground from the battery for my gauges and w/b through the pass door area. Been so long ago i'm going to go look and see how I did it, lol.