In the box:
Amp, adapters for stacking amps together, instructions, warranty and registration cards, various screws and two allen keys - a large one (for the power connector) and a small one (for everything else). Oh, and verification certificates - one for the PDX-F6 (164W@14.4V (0.39 dB of extra power)) and one for the PDX-M12 (1303W@14.4V (0.36 dB of extra power). I think it would have been nice to see testing at a more realistic voltage level - for example my MTX-4160's certificate shows that it was tested at 12.5V, producing 54W per channel at that voltage.
These amplifiers are tiny. Seriously, particularly considering their rated output capabilities. Smaller than the GM-D510 (a class D amp rated @500W into 2 ohms). Considerably smaller than the MTX-4160, which is rated at 30Wx4/4, but capable of 54Wx4/4. So small that I had to fabricate extra brackets to mount them in the usual locations below the front seats. So small that even with the brackets raising the amps by about 3/4 inch, there was still ample space for them below the seats. The image below should give a fairly good idea of its dimensions (that's the front seat area of my Hyundai Tucson)
The use of plugs instead of screw terminals for quick connection is generally a positive feature, though the speaker plugs tended to be difficult to remove once they were inserted. Unfortunately I had to cut off all of the power and speaker spade terminals I used to connect the cables to my previous amps, but I'm hoping this this is going to be a one-way change anyway .
I still have a bit of adjustments to make (gain settings, and x-over points), but I thought I'd give a few first impressions.
Concerning the PDX-F6, I think the upgrade was a generally positive one. It seems to have oodles of clear, clean power on tap, and as I kept turning the volume up the output remained clear until I had to turn it back down because it was too loud for my liking - this is the first amp install I've done where my ears gave out before the amplifier did.
Concerning the PDX-M12, the performance improvement over the previous amplifier (the Pioneer GM-D510) was a lot less noticeable. In fact, in some ways I prefer the GM-D510. While the output seems to be there (the amp is capable of driving my Infinity 122.7W subs to their limits), the Pioneer seemed to be capable of a bit more low-end oomph (and yes, I ensured that the PDX-M12's subsonic filter was off).. It's possible that this may be caused by a x-over or gain setting though, so I'm reserving final judgment on this until I get those two things sorted out.
Overall though, I'm quite happy with the purchase, and looking forward to even better results after I've completed the necessary tweaking.