Electrical power fluctuation
 

For the first time, I noticed my aftermarket head unit's digital display pulsing (Brighter... Dimmer... Brighter... Dimmer) with each thump of the bass response. By turning off the Litronics, the pulsing illumination issue stopped.

I am not running a subwoofer or an aftermarket amp. Apart from the head unit, everything else is stock.

Do I have anything to be concerned about?

Check out my battery thread in the technical forum.

It could be the battery may be weak, have a Group 48R VS 94R battery which is better for upgraded sound systems or a possible grounding issue.

I would suspect a weak battery as well. If this is the case, the headlamps should dim a bit with the bass, too.

Edit: scratch that...I don't know anything about your headlamps, but I'm guessing that they are HID with ballasts. The ballasts would probably even out the power fluctuations and have no noticeable dim. Better indicator would be the dome light, with hl's on and stereo turned up. If the dome light dims, that would lead me to believe that the battery is weak.
However, there are many things that could cause power drain. Could be heat weakening the battery or a failing alternator, also.
I would take it to an auto parts store and have the battery and charging system checked. It's usually free. ;)

Battery getting ready to leave you !!!

Load test the battery, but also load test the alternator; this is a classic sign of a dying voltage regulator.