Bridged amp with electrostatics..

Depends on the amps and the speakers. I use bridged Plinius SA100's into 4 ohm planar ribbon mids/tweeters but that load is purely resistive. These amps were designed to be bridged, unlike many others.

Stats are differerent in that there is a transformer in the chain.

I can't see how it would be possible to bridge an integrated amp like the KW550.