Arduino controlling led strands

hello all,
i have been working on a constant current design for many led’s, up to 60 so far and still adding. i am trying to design large lighting system with a few additional tricks. i have 2 of the 3 ideas working fine but i need help to get on the right path for the last one. i am using a resistor ladder for control of the various sequences.

basically i am doing 5MM, 3.2v, 20mA led’s on a strip for each wheel well, front grill, and underneath of car. i have the voltage at 2.7v across leds @ .4A with 60 led’s and still adding more and adjusting as i go. longest running is 3 hrs and no heating of any kind to be concerned about for resistors, hardly even noticed the heat on mosfet (IRFZ44n), trans(TIP122) is still cold with 2-4.7 OHM 3W paralleled. i have a buck/boost with for steady voltage. it drops to 6.5V once c.c. circuit turns on full load.

i want to program the 328p stand-alone to have the lights brighten and dim to a condenser mic. i know i need to use, carefully, a 386 or like as mini-amp and watch input voltage to A-pin(s) on the 328p. i am stuck at what ic to use, if any. lm3914/15, shift reg… or can i simply have to audio input on analog pin and then still do a pwm control into c.c. circuit with set values out according to V_in from audio? i can use a 50K pot just fine, i have used a MCP41100 just fine so i know the possibility is there, just need help figuring it out.

included a eagle pic of my c.c. circuit.

i am not an expert, do not claim to know everything but i have SOME knowledge to blow a few things up and learn plus several small projects already with ard-uno. i would appreciate some help on this matter to control lights with audio through arduino into c.c. circuit. also, for led strips being far away, would i need to use a cap to help with power line?