[SunSoaked]

I recently got mine installed. For now I'm just running off the Pioneer deck with 4" speakers in the dash. It sounds really good. I'll add an amp and additional speakers in the future.

Regarding the brackets:
I covered the backside with sound deadener along with the back cab wall and floor. I also had some closed cell 1" thick foam laying around that I cut and fit in behind the speakers. This was key to good sound. Speakers and metal mix like oil and water. This is a good compromise for not having enclosed cabinets.
Hope this info is useful for someone.
All those wires were tucked in and dissapeared after I put the insulation pad and floor covering back in.