Modded you can run the amp at .25 ohm. It will run at that but I wouldnt recomend it. .5 ohm ALL day and it makes some really good power.
From what we tested it was about a 1.4-1.5 db difference from 1 ohm to .5 ohm and about another .3-.5 ohm from .5 ohm to .25 ohm. I like the amps. Just dont recomend playin music on the modded amps. Also you have to charge the cap on the modded amps. Make sure that you have the radio paused and volume all the way down. Then hook up the remote wire to the amp. After that un pause the radio roll up to about vol 3-5 and let it play for a couple secs. This way the amp is charged and ready to go. Good luck.
TITE! Thanks i was just curious you answered all my questions and then some my buddy just bought an UN-modded one yesterday off ebay a white one since its un modded will it run no problem at 1 ohm mono? Hes gonna be running it to (2) Premier 3004 SPL's....... Will it stay cool?