Back to your original question - I am unaware of an amplifier currently made by Mcintosh with a model number of 7300. There is the 6300 and the 7000. As to driving the MS5 with these different models, The 6300 would be a light, the 7000 will likely work fine for all but the loudest listening levels, but at those levels, my guess is that you will get the power guard to flicker. The 402 would be my choice.