I have a diehard interstate battery and run a small amp. No dimming of headlights, though map lights dim if I have them on. You may not need to spend the money on an optima, but it may be worth it. I think just a good normal battery with the stuff you already have could be good enough. I love my diehard, the name is very true. I've left my lights on twice and got a jump start and still have no problems. Left them on once for over 2 hours and the car still started up. And I listen to music for 30 minutes with car off and have no problems starting it.
