I installed one on my buddy's jetta, and it worked perfect with a little tuning. He is running one 10 in a bandpass box and it sounds good, and he can still use the steering wheel controls. You just have to tune the converter, first his was really distorted but I played with its adjusters and was able to get everything sounding good.
Now with that said... I would not use it if your running anything more than one smaller sub. I'm not sure it would have the signal strength to run more than one. If your upgrading everything else might as well replace the headunit.
Do the world a favor, hurt a honda...
Iro 3" lift with pro comp 9000es shocks, adjustable trackbar, led rock lights, all interior lights converted to leds, two 10" kicker comp with Kenwood 600 watt amp
Zombie Outbreak Response Unit #396