OK, but the question regarding how they compare to a factory HD-2 still remains. (As well as how a Max Flow compares to an HD-2).
The HD-2s have been running pretty strong for me, and I like the idea of a pleated filter, a lot more surface area and harder to clog.
Maybe I will switch back & forth at the GTG and see how they do in timed cuts. I'm also interested in how long before they clog up compared to factory HD-2s. The price on them is great, but that does not mean they are a bargain!
But I will be trying them especially on my 044 that seems to spit back a lot (I'll run the foam in that one, since there is no spitback guard in a 044).