have an ONKYO TX NR646 7.1 i want to use another external amplifier for the FRONT L and R to power up my 2 DS18 PRO10"/channel(300W each), total of around 700watts (plus the tweeter)/rms /channel.since ONKYO only offers about around 120Watts/channel.any suggestion....i can use the PRE OUTS for this, but does it also offers the same sound quality compare to FRONT L and R speaker terminal?