A challenge for me is to add a second amp to power the dash and soundbar speakers for when I remove the box in the back. Maybe a small one located between the front seats or under the dash (the latter would overheat quickly unless i find a way to cool it)

You could try an idea that I have been toying with for my jeep... Mounting one or both of my amps under the hood. I have a TurboCity airfilter on my jeep so the stock airfilter box is no longer used. I think it is big enough to hold one or maybe two small amps and would be pretty easy to waterproof. Right now I have two 8 inch subs in a custom box under the rear seat, but I have been wanting to replace them with two 10s built into the hide-a-trunk in the back and if I do that I need to relocate the amps that are currently there.

-Mike