The 70x series does have good amps, but most receivers just don't have the oomph to run a full compliment of Studios properly, certainly not one involving 100s, IMHO. The original choice of going with the 60s, with them crossed over would be the right way to go, but as he said, they don't have them right now. I have run both 40s and 20s in my systems and they really do like a lot of power. They sound good with average power, but they really show their true capabilities with more of it. With my receiver @ 120w, the 40s still felt like they could be pushed harder, though I do have a large room. My buddy had 20s powered by a Marantz 9300 pushing 140w and even in a HUGE room, they sounded very happy.