Volvo Multi-Band Antennas

Our company trucks are Volvo VNL's and they have those stock mutlti-band antenna's with the copper wiring up and down the whip. I have a Cobra 29 LX that has been peaked and tuned and talks well. For the most part, the Volvo antenna's work okay. I get a great SWR reading and no warning lights. But, I notice the receive capabilities seem restricted. A driver right ahead of me can be talking to someone far away and I can not hear that other person until he gets closer. I also notice, that when I talk to a passing company driver, we can talk for about 15 seconds at most.

Has anyone had experience with using these and even changing them out?? I see them all over, but been pondering swapping them with a pair of Wilson 2000's, but not sure it's worth it. Maybe that's just how my radio is tuned.