Car underglow/Color Organ

I have started on a project, but have hit a wall.

Car underglow kits are too basic, using PWM through FET Channels, I intend to control RGB LED Strips with an arduino for full spectrum color, including a mode for color chaser (going through the entire spectrum automatically instead of a single user set color). The part I am having difficulty with are the two additional intended modes "Response" and "Chaser Response". I want to press mode and have the set color flash on every time the bass hits in the music I am listening to (audio passthrough). Pressing mode again, I want a different color (most likely from a list of 64 or so presets) to pulse on everytime the bass hits on the car system.

Programming won't be a problem. I am curious as to what hardware approach to take? Audio EQ IC, A2DC, etc? How do I get the 20-200Hz Range to trigger a change in an Analog or Digital Pin?

For music reading - I use this shield … 7 band EQ reading with build in multiplexer (in the chip).

Ok, I looked into the graphic equalizer shield, but aside from the noise I read about in the comments, that gives me the option of triggering on 63Hz and 160 Hz two specific frequencies in the spectrum (with user adjustment per “song”) of 20Hz to 200Hz which is considered by Wikipedia to be considered “bass”, while THX considers frequencies 80Hz and lower to bass, this isn’t a theater, it’s a car. I hope this doesn’t disqualify me from receiving assistance, but this is for what I hope becomes a Product.

One thought I had (be honest even if brutally so) was to actually include the circuit for an LED color organ from http://blog.makezine.com/archive/2010/10/circuit-skills-led-color-organ-spon.html but instead of having the final transistor array switch on and off LED’s I thought about having them trigger a digital low on an input pin once this mode was selected.