I have a friend that is looking for some good ceiling speakers and I came across the HTD speakers. I read many good reviews and every said that they have great customer support. My question is what is the main difference between the multi-purpose speakers vs the high def speakers. Have anyone herd them side by side? I am talking about the 8" HTD-R3S multi-purpose, I think its the level 3 one vs 8" AL-R80 which sells for $60 more per pair. From the info off the site, the AL-R80 has adjustable tweeter level. How important is that? Will that make a big difference?