Well, I ended up drilling a hole in the firewall and it worked out quite nicely, actually. If you'll look on the firewall next to the driver-side where there's a place to mount an engine stability bar, there's a slightly puffed up little place on the firewall about 6 inches down. All i did was run a knife down the edges of this puffy material and it popped right out - this is a place where the manufacturer WANTS you to run anything through, if you do. The firewall isn't but about 1/8 of an inch thick, so drilling a hole with a fairly small drill bit and stepping it up to a larger drillbit wasn't a problem. I am now a proud owner of a working 650W Kenwood amplifier, and two 12" Kenwood Tornado subwoofers

-I'll post pics when I get the chance.