Someone, either here or on the DTR, tried an FS-2500 hoping to clean up the soot in their oil. It did not clean the soot, as advertised. I believe they tried to return the filter to Filtration Solutions.
I sent away for their advertising & demo CD. I must admit, it was quite convincing. They were using carbon black to simulate the soot. In their test, the filter worked very well.
The FS-2500 seems to be quite pricey, also.
The "toilet paper" filters seem to work very well & the filter elements are cheap. The downside that I see is that the TP has to be changed, frequently (every couple thousand miles), for them to work properly. And, you have to add "make-up" oil when changing the filter. They seem to be more inconvenient than some of the other products that are avaliable along with the cost of fresh oil at each filter change.
The Oilguard & the new Amsoil, high efficiency, filter have peaked my interest.
In Filtration Solutions defense, I believe I read that they are working on a new, higher efficiency filter, at this time.
Joe F. (Buffalo)