The consensus agrees with laboratory data (aka, gallery renders made with my products); if you don't include BUM files, P4 users won't use bumps. But it also appears that if you DO include BUM files, many P4 users still won't use bumps. So I concur. Throw the BUMs out! Besides -- anyone who uses P4 is going to be either someone who has been using Poser for a while, or someone who has gotten used to figuring out how to maintain compatibility in a rapidly changing (notice I didn't say "advancing") computer world. Aka, they are the most likely Poser users to be able to figure out a bump-map conversion. Laetia and I were just discussing this issue, and our general slant seems to be that the cleanest way to maintain P4 bump compatibility is to provide Bump Poses in the download; MAT poses that do nothing but inject P4-style BUMs. With the cross-compatibility of PP jpegs and P5 displacment/gradient nodes, it then becomes possible to have a single MAT pose that serves the other versions of Poser.