I had some audio equipment left over from my Civic, and tried it out on my '04 Accord. I bought adapters to plug into the factory speaker plugs in the rear, then ran the leads directly into my Alpine MRP-T130 2 channel amp. (It accepts high power inputs) I hooked it up to 2 10" Pyle drivers in a box I built. It has plenty of bass for me...in fact, I had to turn the gain down on the amp and drop the bass on the head unit to -2 to match the front speakers.

Next, I experimented with an old EQX unit I have (1985). It required me to use a line-level adapter since the old ones didn't have speaker level input. I am currently running the sub amp through it, and shaped the bass the way I like it. Maybe I'll bi-amp the car at some point and get the full potential out of the EQX ;o)

I've not had any objectionable distortion, and I've had zero noise.

The amp and EQX are mounted on the sub box. I made all the power connections with a molex connector. All I have to do is disconnect the speaker plugs and the molex, reconnect to the factory 6 x 9s, and I can have my trunk back when I need it.

In my opinion, the stock system in my LX doesn't have nearly enough treble (I'm at +6) If you use a sub, it takes a little experimentation to get a balanced sound that's not muddy.