sibilence....any cures out there?

Sibilance is usually evident in an ultra detailed tweeter. Cause is a usually a bright source. Many recordings (vinyl or CD) are not the best, which can excite the tweeter. Cables can tone things down a bit, but if it's really a problem you might look at your amp and or source. A chain of ultra revealing components can get harsh on all but the best of recordings. One or the other, or both, may be the issue. Or maybe the tweeter in the Nola is just not to your liking.

Did you have this issue with your previous speakers?

Swampdog, Try some absorbtion at the first reflection points along the side wall and ceiling, if possable try some on the back wall also. Sibilence can also be caused from the high frequencies bouncing around the room.

do u have a bright sounding room with slap echo problems?

You could try a product like Jim Goulding's Diffraction Be Gone: http://www.diffractionbegone.com/

You could even DIY your own to see if it gets rid of the problem. All you need is some self-adhesive felt from your local hardware store and a pair of scissors :)

Replace the capacitor to the tweeter with some vintage paper
In oil ones.