Ok so we are working on the wagon amp rack and ran into a bit of a problem. The model we made replaces the factory cargo tray that sits over the spare. Our amp rack sits about 1/4 of an inch above the spare. The problem we didn't notice sooner is to do with the actual cover that hinges and covers that up. It is not totally flat on the underneath side. It has some areas that hang down into the amp rack space making it hard to put large amps in there.
We can't make the amp rack any lower or else you'll lose the spare. Right now you can fit anything that is about 2.375 inches max height. If it's taller it will hit the cover. We're thinking about making a new cover to replace the factory one that will have better ventilation and allow for taller amps. It will raise that portion of the floor a bit but it would be strong enough to still support stuff.
Here's a couple of pics of the original and our black gelcoat version. Let us know what you guys think! We're trying to make it work for multiple amps.