Well, to quote the FS2500 people:
"Sir, the custom kit for your pickup costs $429.00, this is a savings of $100.00 for a limited time. Replacement filters are $26.95 each and last 10,000 miles. Shipping is $25.00.
Jim Williamson"
And, checking the OilGuard web site, their replacement filters (EPS-20F) are $24 each, plus shipping, in packs of three or twelve.
So, if it's the replacement filter price that you're concerned with, you'd be jumping from the frying pan into the fire by changing to the FS2500. Plus, you'd spend the "less than $250 on EBAY" for the privilege.
Fleetguard has a StrataPore full flow filter (LF3974) that might add some filtering to help the OilGuard. I just bought some for my truck. I don't have a bypass oil filter on mine, yet. Still trying to decide which one, if any, to use.
Just a thought, but is the OilGuard housing getting hot after the engine reaches operating temp? If it's not getting oil flow, it won't. The video on the FS2500 web site shows black hydraulic fluid being cleaned to clear, but I don't pretend to know if that proves anything.