SE,

After initial alignment, I used a Sharpie to mark the points at which both the sled and the Kenwood lined up with the Subaru brackets. Then I pulled the sled, Kenwood and brackets into the kitchen, aligned the pieces, made some more marks, and started drilling. None of the original holes were in the correct position, so I drilled new holes for the OEM screws to hold the Kenwood. Then I drilled throught bracket/sled on each side, a hole large enough for a flat head #8 machine screw. This screw goes in through the inside of the sled and is secured by a nylock nut on the outside of the Subaru brackets. With this done, I just replaced the whole bracket/Kenwood/sled assembly back in the car.

No, you don't need to weld anything in this scenario. However, doing it the way I did required that you cut the bezel enough to fit around the lips of the sled. When I redo it, I want to make it so that the sled can go in *after* the bezel snaps in place so that the hole cut in the bezel can be smaller and neater. This will require fixing those nylocks to the brackets so that I can insert sled at the very end then reach in and thread the machine screws to hold the sled. Welding would do the trick (but you'd need to get stainless nylocks from someplace like West Marine and there's a chance the tack welding could melt the nylon); another option is something like Devcon Metal Welder (supposed to work on stainless) or even JB Weld, a couple of "metal epoxies"; I'm going to try the Devcon.

Other advice?:

I was going to put 2 securing nuts on each side of the sled, but 1 seems to do the trick given how tightly it fits in a 2 head unit install. If I used #6 flat head machine screws, they would project even less into the interior of the sled, but would be harder to thread and drive. I'll stick with #8, but may try to bevel the sled holes a bit more so they project less.

I cut a small square of that Ctrutchfield-supplied ABS sheet and put it over the heater controls (under the sled) to keep stereo wires from fouling heater and vice versa.

Take your time drilling stainless!

Jim