Had a return client come in for a full DD Audio system install.  I recently installed a single 12" DD Audio package system into his car, with about 350 watts of power.  It was good enough to get him into the spirit of good sound.  A few months later he's back for more....in a big way.

We kept the 600 watt amp I installed, but we swapped out for (2) two 12" 500 series woofers in a custom made slot ported box.
I replaced the stock speakers (which were factory amplified premium speakers) with DD's CS5.2 and CS6.5 component speakers to provide with crisp, clear sound. Installed the crossovers in the doors and hardwired them back to the new 4 channel DD Audio amplifier.

Originally I installed the 600 watt mono amp on the back seat, but seeing as how the 4 channel amp was the same size, there just wasn't enough room for this to happen.  So, after a few minutes of playing around with location, up under the deck lid was where they both went.
Install was a bit difficult, as in order to get them up there and miss the subwoofer box and the deck lid when it shuts, I had to put them in JUST the right spot.  Now the amps are completely hidden and out of the way, and if the box needs to be removed, you can't even tell the car has an aftermarket system installed......just the way I like it.

Without any sound deadening installed, this system actually sounded amazing....this is DD's entry level system, and I'm more than impressed with it.

Customer will be back for sound deadening and more fire power under the hood (Battery)....but for now, he's one happy customer.

Well, shortly after the first system went in the 'dairy truck' last year, the truck took a crap on the owner (thanks to a mouse in the fuse box).  So....now we have almost the same components but a different truck.

2009 GMC Sierra
Pioneer 3200 Deck with Steering Wheel Controls
Memphis Audio 500 watt Street Reference Mono Amp
12" JL Audio Subwoofer in an old body style GM sub box

Put the amp behind the seat (back carpet was already cut for an amp.....well, chewed up)
Bass Knob was put down low
Deck pushed the stock speakers better than the stock deck could

All in all....good sounding system

Busted out a quick one Saturday morning.
2008 Chevy Cobalt getting a new deck (Clarion), rear speakers (MTX) and an amp/sub combo (MTX).
Everything was straight forward and after wards a huge improvement from stock (of course).

Cheers