Just remember your electrical system is only as good as your weakest link. I'm kind of curious why you're running into dimming problems. I used to run a rockford 1500bd amp and a 300watt 4 channel one on the stock electrical. Never had any problems. I always turned down my music when idling and never had it on with the car not running.

Since then I have picked up a Die Hard Platinum bat. Dropped right and it cranks better than it ever did with the stock one.