for those who don't know...
the plant that made the Quart stuff in Germany makes the JL separates...not 10, 12,15,13,18 inch woofers...just the high end speakers.
Translation...the JL XR line is pretty much the Quart Premium line with a different spec'd tweeter (aluminum dome in JL's case). The Quart Q series are cousins to JL's new ZR line...even the tight tolerance spec's are the same.