Best 40 to 50k used speakers

I can't imagine for 50K you could do much better from a performance perspective than a pair of brand new JBL M2s, their SUB18, and their matching amplifiers.  This assumes an existing room with good H:W:D ratios, properly properly constructed, damped and diffused.  I realize many audiophiles hear with their eyes every bit as much as, if not more than their ears.  If that's you, ignore this and just get the pretty ones. 

@eganmedia I completely agree with you, i care much more about the sound quality than the fancy look.That's why i'm also looking at brands like ATC and Spectral audio.

If you have the opportunity to audition the A5 , do it !!! 
I will also recommend YG Hailey , if you're tast is in the aluminum corner ...
Mine is ..

For that kind of money you could get the monitor audio platinum 500 ll for $30,000 brand new and those speakers will beat speakers that are three or four times the price. Check them out.

Dude jump on somthing ASAP!!!