what is the method used to make the oil bath setup refered to ? I have a 54' GMC pick-up that came with one as standard and they claimed that an oil bath air cleaner was the most effective type there was ---and the research is only 53 years old. But the idea of a permanent filter is appealing if it really is effective. how about an oil bath prefilter andthen the stock paper set up too, maybe only have to change the paper every two years...