I would order the 7125 because you have the 30 day trial.

Also;

The M80 are very efficient and an easy 4 ohm load. I have the 80s and am continually surprised how little power they use for such a big sound. I can see on the readouts of my amp that the mains rarely go higher than 10 watts.

My whole system including the TV pulls less than 6 amps.

Use the difference in the price of the 7125 and 770 to upgrade your sub to an EP500. It will make a HUGE difference in your HT experience.

What are you using to drive the 80s now?