Is it really 135 WPC on all channels driven or just two channels? Outlaw specs its amps at all channels driven to give you an honest idea of their power output. Many receivers are spec'd with two or even one channel driven. It helps to compare apples to apples. Bear in mind that doubling the power of your amp will not result in a doubling of the volume output. It will provide more headroom for the amps response but only increase output by 3 db SPL. If the Onkyo honestly puts out 135 WPC I would not expect a huge change from the 7700. However, I would be surprised in it is rated at real world watts and not showroom watts.