What are the differant methods used to run wires and tubing from the engine compartment to inside the cab?

Drill a hole, put a rubber grommet on there. I'd probably silicone it to keep the edges of the hole from rusting. Run your wires through and then seal those with silicone.

You can also run more through the existing grommet left of the steering shaft. I have a lot through that one by slicing the rubber a bit running wire with a lubed,(soap), fish wire, then a bit of silicone. Hey Waskier, how are the Yokohamas doing for you?

Use the rubber grommet already there. That's where Banks says to run them for their 6-Gun. Helps to have two people.

If you pull back the insulation on the firewall under the fenderbrace on the driver side, you will see a divot in the firewall, look under the dash at this same location and you will see a perferated spot in the insulation with a tab in it. Pull out this tab and drill through the firewall at the divot, then use a grommet and silicone to seal as needed. Problem with piercing the rubber boots that are already there is they dont look as clean and could cause dealer issues. also leaks are a possibility.

I was told and it shows on the build details that with the plow prep package that there is a hole already there with a grommet.

Lord knows I never found it! :(
Pete

Far as I can tell GM omited the fire wall "plug" as part of the snow plow prep- none of the trucks I did this year, 04 or 05 had the plug like the 01-03's do. I agree with Eric. Pull back the insulation. look for the plug inside above the electrical block by your left foot and drill away. I use a buytl compound to plug the hole after we run the plow wires in to the cab, it's easier to remove if you want add something else through the same hole. CAUTION don't drill to fast if you slip you can cut some wire that you would rather not.