Hey Greg.... I tend to agree with the others here... it sounds like you need a good quality amp... to me it seems like your driving those 40's into higher levels of distortion.... As j_garcia has plainly stated that he has had no troubles with his 40's with a better quality amp.... and for sure that 659 will show no more love to a set of 100's then it does the 40's.
I tend to go overboard, and think into the future.... with that said... I would go with as much amp as you can afford.... I really like to do the whole front stage the same... like a 3 channel amp, but usually those are harder to find.
I hate to suggest that you get a 7 channel amp and not use all the channels, but the Emotiva IPS-1 looks like a good unit. Or maybe you could find a good deal on a 5 channel amp.... Take your time, and turn that system down until you find some good power...
If your dealers is offering that Upgrade path for the year, you could always trade up to the 100's later, after you got the Amp....
