I've got millions of miles racked up on fleet vehicles where I work. I've always used Napa Gold filters, which are Wix filters that are rebranded for Napa. Never had an issue using them, synthetic oil or conventional. ONE time, somebody took a vehicle to a quickie oil lube place while on a trip, because the "change oil" light came on. That place used a cheap Fram filter, which collapsed the filter media within a week and trashed the engine. I posted a whole thread with pictures on here about that incident. That filter used cardboard inners, not kidding. I know Fram makes 'better' filters, but I wouldn't touch a Fram.
Like Drew, I wouldn't hesitate to use a FL1A on any stocker engine, or a FL1A HP on a performance engine. I also wouldn't hesitate to use a Wix or Napa Gold filter.
On my Mach 1, I use a Canton billet filter housing with replaceable filter cartridges. They have no bypass and are easily inspected when you replace the cartridge. Some people have issues with the no bypass, but I don't see any issues when I start my engine. It builds pressure as quickly as any other engine I've seen, regardless of the filter being used, and this is with me running 20w-50 VR1 racing oil. Been through 2 Drag Weeks and quite a few street miles with it and the filters come out looking clean and good every time.
