I have mine tucked away because I have to haul stuff in the back every now and then...
Custom car stereo in Houston did the work. It's a JL W1 10" in a sealed box powered by a 250 watt PPI amp (IIRC), soon to be a PPI PCX280, with the sub amp being used to power the front components. And the amp is bolted down, it is not loose in there. It is unbolted in the picture b/c I was working on it. Sounds great, just loud enough without being obnoxious, but it bumps if you want it to.
And the sub and amp have both survived my car getting broken into twice, if I had it sitting in the cargo area with the amp stashed under a seat, it would be long gone.