HP, welcome. Although I'm not all that familiar with "metal", the dynamic classical music that I prefer gets very "loud and heavy" indeed at times. From your mention of the Epic Master systems, I take it that you'd like to hold the cost down to around $1,400, but that you may be wondering about a more powerful sub. With your 6-7' listening distance, the M22s would work extremely well when supported by a strong sub. For something in the $400 area you might consider the HSU VTF-1 or SVS PB-10 to help with your heavier stuff. Instead of the VP-100, you might consider using an M2 vertically, which works very well. The QS4s should be fine. On your diagram, your "rear" speakers, which are actually side surrounds in a 5.1 setup, could be separated a little more widely than is shown, to give more of a side effect.
Note also than you can get a 10% discount by ordering your speakers from the Outlet(new, with possibly a small cosmetic blemish), and an additional 5% discount for five items at a time.
