PMC TB-2 to "+" Upgrade?


I have a pair of PMC TB-2 monitors which I really enjoy. I'd considered pursuing an upgrade in the form of a larger model to deepen the bass response, but the recent model and price changes have made that rather unlikely for the foreseeable future.

I'm told by PMC that upgrade kits to the "+" designation are still available. The primary change seems to be going from a metal to a fabric tweeter, plus a corresponding change to the crossover and different lining for the transmission line.

Has anyone done the upgrade or heard both models, and can give me some idea what sonic differences it entails? I'm willing to put some money into them as they will be my speakers going forward for at least three or four years.