UPDATE: good news, the problem was in the wiring, i guess too much stress on the amp with the .67 ohm load, so i wired it in series/parallel like the diagram above to 2.66 ohms and all is good now. Given that each sub is only seeing a little more than 150 watts it sounds pretty good. he needs another amp for sure and he should be in business. thanks for all the help guys, much appreciated!