Like the others here have said, don't run two radar detectors at the same time - in the majority of cases, you're going to run into issues, and what's worse, not all of these issues are as easily "visualized" as what you saw in terms of the X-band cross-talk:
Radar Detector Tests and Reviews by Guys of LIDAR
This
GOL article explains the technical considerations.
Yes, there are some interesting/special "combos" that allow for a "dual detector" scenario to be possible, but for a beginning detector user, it's better to just stick to the
GOL's suggestions above, and simply not worry about trying to find such a setup.
Just stick with one detector, you'll be better off. In a tactical sense, it also will allow you to breed intimate familiarity with how your detector reports different threats, which is VITAL to your ability to properly act as the "final filter," and to respond to its alerts in the appropriate manner.
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With respect to jammers, I would, at this point in time, recommend (in no particular order) looking towards a dual-head setup of either the Laser Interceptor or AntiLaser or a three-head setup of the Laser Pro Park, due to the frontal profile and hardpoint concerns on your large vehicle.
With the Blinder, you'll want to use the four-head setup (the M45), and even then, it may not e able to offer you the area-coverage you need, despite its requirements for mounting real-estate.