Ill give you a story about running at half ohm. I bought an amp that was rated and warenteed at half ohm. Ran 1/0 wire for my big 4 and to the rear distribution blocks. No extra batts and a stock 110 amp alt. Ran it at 2 ohms to break in subs. After two weeks i fliped it to. 5 and yes it was definatly an audible difference. About two weeks later i notice its not playing and that all the fuses are blown in the amp. Replace the fuses and switch it on. Instant magic smoke, wish i had a camera, that would have been a cool vid. Long story short they didnt have an exact replacement for the amp so they sent me the next step up at no more cost to me exept shipping the fried one back to them. I invested in another pos run and a neg run and two batts in the back. Iv been running on this setup for a while with a few multi hour runs on the highway with no probs. Would i recomend. 5 ? Hell no.