I would start by using another amp entirely. Have you tried them in NON-biamped config? That's where I would start before replacing speaker drivers, or sending amps in for service. Also, if you have identical amps I would vertically biamp them, though this shouldn't effect the issue you have.
I have VR4 gen III's and they don't require 200 watts to sound good (indeed they sound wonderful with a 35 watt tube amp (non-biamped), and I normally drive them with a 140 watt ss amps in vertical biamp config. So testing them with your lower power amp shouldn't be an issue at all. Also, unless there's a significant sensitivity difference with your top and bottom amp, driving the mid/hi module with the EX442 shouldn't be an issue either.
I have VR4 gen III's and they don't require 200 watts to sound good (indeed they sound wonderful with a 35 watt tube amp (non-biamped), and I normally drive them with a 140 watt ss amps in vertical biamp config. So testing them with your lower power amp shouldn't be an issue at all. Also, unless there's a significant sensitivity difference with your top and bottom amp, driving the mid/hi module with the EX442 shouldn't be an issue either.