Sound System...car being funky

Hey everyone, well I had my Rockford P2's put in.I just have a quick question to ask..whenever I have my rf's turned up loud my regular headlights dim, and my interior lights dim aswell. At night when I turn my headlights on my system would cut off but quickly come back on and will keep doing it untill I turn it down. Also I noticed when I make sharp turns it would also cut off but come back on and sometimes even when I accelerate.
Also does the COLD affect how well my system will play? WHen I had them installed they were booming! And it was a warm day like in the 60's..I could get the volume as loud as 35 and now it's more like 25. Any ideas??

I remember my pioneer deck diming when i had the volume turned way up. You can try a hyper grounding kit in your engine bay and it might help. Or you can re-wiring your deck to a different power source thats more direct to the battery supply. Otherwise you just gotta deal with that.

do you have a capacitor? they work wonders. or the big 3, which i think is what cody is talking about. http://www.j-body.org/forums/read.php?f=4&i=117446&t=113629&p=2