It's smart to choose an amp for the long haul. The difference in power consumption values is curious, but I can't explain why it might be - I'd expect the Aragon to match the 7500 (1800W is the limit simply because that's all that an amp with a single power connection can get from the standard 15A circuit). THX Ultra2 for an amp will mean an assortment of bench tests, I'd assume, but some of the big selling points of Ultra2 are software - things that show up in Ultra2 receivers or processors, not amps. Based as much on Aragon's rep as the Ultra2 certification, I'd expect the 3005 to certainly match the 7500, but I don't know what might be true beyond that. Like you, I struck out pretty thoroughly in my bit of web searching for info on the 3005 in relation to other things, although I didn't dig into it real deeply. Maybe some others around here have some thoughts to toss into the mix.