The first claim is that the amplifier can work with 1ohm or 2ohm load. I don't know about others, but I still would not run this amplifier at 1ohm, unless I was on a camping trip and needed to fry some eggs. I would expect the amp to run very hot and less efficiently at 1ohm. This should be tried only with proper install, and/or additional forced cooling.
The second item is the Q-tune technology. It boosts the output near the high pass crossover frequency. It's most useful for tuning subwoofers in a sealed box. Think of a subwoofer that normally in a sealed box will experience a natural roll off at the deepest bass frequencies. If you would like to boost the response at lower frequencies, provided you have enough excursion and power headroom, you change the high pass (subsonic) to say 20Hz, and then boost the q-tune. So it's kind of like variable frequency bass boost which is a lot more useful than the standard useless bass boost on most amplifiers.
