All, I have Martin Logan Motion 12 speakers(4 ohms) driven by Pioneer VSX-32(8 ohms). I want to get an external amp, like the Bryston 4B ST, and use the VSX-32 as a preamp. These are the only speakers for now, and I mainly use them for classical music listening. Would this external amp make a big improvement in sounding, I wonder if it is worth the extra cost. Thanks!