Troels Gravesen's crossover for the JBL L100 centu

Has anyone out there tried Troels Gravesen's crossover design for the JBL L100 Century? I'm wondering if it's worth the current $600 for the kits to do the upgrade. Anyone heard the results? In particular I want to know if they tame the speakers propensity to be bass heavy and thump. I know that's kind of the point of these speakers, but I listen to more than Talking Heads, after all.

I'd appreciate opinions from anyone who's heard the results ... or anyone who has opinions.

cheers ...