Have been reading the many posts about pre and post filtering. I have a big Cat filter as a pre filter to the OEM but it hasn't been on long enough to change. I considered a lift pump but decided against one because I think it would only serve to force dirt thru the filter that would normally be caught by the filter. Also considered a post OEM filter but it doesn't make sense to me to clog that expensive OEM up first and have to change it while the post filter is still almost new in appearance. Some of the pictures I've looked at seem to bear my theory out. Plan to put 10k mles on both filters and then opeate on them and see if that OEM is still clean like I think it should be.

That my plan also. I will pull both filters at 10K, and determine future change intervals. I curently running a 10u primary, and am also considering changing to a 2u, but I don't want too much resistance to flow.