Maximum operating pressure on most panels is over 30 PSI (mine are 40 PSI) so I really don't think a 2 PSI pressure reduction is going to increase the life of the panels by much. With an operating pressure of 20 PSI, that is only a 10% change.
In addition, most solar systems are installed on two story roofs where the panel pressure is a lot less than the filter pressure reading. When I measured my panel pressure on the roof, it was about 19 PSI lower than the filter. 11 PSI accounts for the static elevation rise (25 ft) and another 8 PSI dynamic loss in the filter, pipe and valves on the way up. The panels themselves only drop the pressure by 5 PSI so the exit pressure is about 4 PSI. 9-4 PSI is not that much pressure. Even panels installed on a one story roof will drop the pressure by half of what I saw or about 10 PSI.
However, if the panels are installed on the ground and the filter pressure is close to 30 PSI, then I might be a little concerned about pressure. In that case, a bypass might be in order because the flow rate is probably too high in the panels causing excess loss.