Best 5 channel amp for Acoustic Zen Adagos

Hey guys, first time here. I have a 5.1 withe the adagos ran off of an Arcam P1. Its a good amp, but I think it lacks pop. It's a 150 x7 and you cant bi-wire the speakers. What's a good upgrade that wont kill my bank account. New or used.
Thanks in advance
Mike