Did the big three upgrade still experiencing dimming what to do next to try and resolve?

I'm running two kenwood exceleon amp 505 watts rms x 1 at 4 ohms running them at two ohm so I should be getting more than that out of them. Hooked up to two kicker L5 12". Each one has it's own 4 gauge power wire and 1 farad cap. everything has it own ground wire hooked up to different spots. Big three I used 0 gauge wire i did ground the battery and engine to the same spot should I try changing that?