Any Proac Supertower Owners Out There?

The mid/low drivers in my supertowers are starting to go (I've already glued the rubber surround on one and the others are very thin and delicate) but Proac no longer has the original drivers for replacement. They're now recommending different, considerably heavier and more expensive ($200 per driver) ones which they claim would be an upgrade. The guy who used to carry these speakers - but is no longer a Proac dealer - says that the heavier drivers would result in a much worse sounding speaker. Who's right? Has anyone done the replacement? Or, alternatively, should I buy some other brand of driver (scan-speak?) or just save my pennies and get the Proac 3.8? Thoughts? Thanks, gon-ers.