Can anybody tell me the best way of going about bi-amping the front channels of my Marantz sr-9300 receiver? I understand that I can't use my unused rear channels to biamp, but can I use the front amps from the receiver and add two separate mono amps? If so, what mono amps should I use? Does they need to match the receiver's amps? The Marantz MA6100 mono amp looks good (in that it's quite compact) but is only rated at 125W into 8 ohms, compared to the receiver's 140W. Is that a problem? Is it in fact not possible to use the receiver's amps in this way, meaning I'd need four mono amps (which I then wouldn't bother with)? Any advice on all this would be gratefully received.