Hi, I`m new here, glad to be in this community. I have a question: i currently own a PM-15S1 Marantz amp and a CDP Marantz 15S1, speakers are B&W CM7. I am looking into bi amping my system and i wonder whether the second amp should be different from the first one: 1. purchasing another identical amp is a good idea? (PM-15S1 costs approx. 800 usd in Japan right now) 2. should i go up the scale and purchase a higher grade amp from Marantz? (PM-11S1 for example, which goes for about 2,800 usd at the current prices). In other words, do i get a better sound if the second amp (which would be the master amp in the system) is of higher grade? I would prefer to stay with the same type of amp, since obviously its cheaper. Any input would be greatly appreciated. Thank you.