To quote the Hastings tech, Gina Johnikins, (they make the Baldwin filters):
"The micron rating of the B50 is 2 and it is 98.75% efficient at this micron size.
Thanks for the inquiry,
Gina"
I've already checked into it, and I'll be using the Baldwin 0B1305 base with either the B50 or the B164 filter. The B164 is just the longer version of the B50.
I was quoted $429 (including a $100 discount) for an FS2500 bypass filter setup. I can filter to 2 microns at 98.75% efficiency for only about $60. And, the replacement filters will be about $6 instead of $22.
I can use the money, that would be otherwise wasted, for other mods, like gauges.