Pat, this was a bit hard to follow; in your first post you said that things were better with the VP150, then you said that going from the VP180 to the VP150 would result in shutdown, but going from VP150 to VP180 wouldn't. In any case this doesn't seem likely to be an amplification problem; a short in the connecting wires or in the internal wiring in the center speaker which results in shutdown would appear to be a more likely suspect.
As to a new receiver, I'd suggest that you disregard that Denon/Pioneer comparison. As htnut commented, there's no way that anyone should be "blown away" by such a comparison if the test was fair and honest. These units are quite similar in respect to basic amplification and it's unlikely that a correctly run test would reveal any audible difference, much less one of "blow away" magnitude.
