Starting from scratch with 2004 accord sedan

Good evening everybody.

I am new to this forum and I just got myself an '04 accord. I love the car but there are a few little things I would like to improve upon. The factory system in it sounds nice but it doesn't quite have enough bass punch to my liking. It needs a tad more.

Could I accomplish this simply by replacing the factory 6x9's in the rear deck with something else? Perhaps something by focal and powered by a 50x4 amp (I would also replace the front speakers as well).

I would like to keep the factory radio and use LOC's for the amps. I thought about getting an eclipse cd7000 head unit to put in there. But this car has that crazy radio/climate control combo panel and the only integration replacement panel is this one Honda Accord Factory Integration Adapter Factory stereo integration adapter for 2003-up Honda AccordWith heating, ventilation, and AC controls at Crutchfield.com but the reviews on that thing are not very flattering. There are complaints of cheap quality....buttons and knobs falling off and so forth. There is also another bracket I can use below the dash but I want to keep that little cubby hole down there.

Do any of you accord owners have this adapter panel in there and if so is it as cheaply made as some folks say it is?