I run WMO in my 1985 6.2L M1008. I'm looking at a 7.3L psd now and plan to run it in there too. You would have to be stupid to dump unfiltered WMO into your tank. Risk to your IP is high and you'll have to change your filters often. Pre filtering systems with pumps are complicated and can cost a lot over time with filter replacements. By far the best way to go is to get a centrifuge. You can get a good 'fuge with bowl and motor for about $700 but you'll never have to change a filter. All you do is clean out the bowl of the 'fuge every now and then. A good centrifuge will remove particles down to .5 microns. The best part is that you can gravity feed the centrifuge. I'll try to find the guy I found before that sells good centrifuges for a good price. I've heard of guys processing up to 50 gal/hr.

Edit: Here is the cheapest/best centrifuge site I've found. I actually know this guy.
http://www.wolverinetechnologiesllc....fugeindex.html