I just recently noticed, my tail lights aren’t working, my headlights, both bottom turn lights work and brake lights work. I recently installed a head unit on the car, could that be it? i have an 05 convertible Z btw.

 

What have you done to troubleshoot the issue? Anything or just come on here and post about it?

 

If you worked on your stereo, make sure you didn't forget to plug in your hazard light switch above the shift bezel (integrated in the center dash waterfall). That's the only part of the exterior light circuitry that I can think of that could have caused an issue from working on your stereo. This is of course assuming you didn't hack or splice into wiring under your steering column.
-Icer