The amp was secured using the 4 screws that is comes with and goes right threw the plastic panel I did this a year ago in California and I did it 4 weeks ago in the nismo I did no problems.
The pdx is not 1 ohm stable nor as I said that is is not really going to push two 10's hard like you are saying "bass happy". You would need something like a 800 watt amp to really push two subs of any rating as hard as you want.
all the sub wiring diagram can be found here. As long as your final load is 2 ohms or up you are fine. Just keep in mind that if a amp is putting out 400 watts and your pushing 2 subs that they are only going to get 200 watts each at full volume and full gain and probably more like 140 at normal listening volumes.
Car Alarm, Car Stereo, Mobile Video, and Cruise Control Info for Installers click on sub wiring diagrams.