im quite lost on these racor filters-. Several questions: The square filter that our trucks came with- What micron is that? And how is it replaced? Element, or whole block? Is it worth getting it agian, or getting the racor? Second question, dunno if anyone is running Waste Vegetable Oil (WVO)- I would assume Im supposed to run this to at least the same quality as my regular diesel- yet I see people running things like 28 microns. is that a bad injector clogging deal? What is the preferred micron filtration. I've heard anywhere from 2-28, which is a great range.