Absolutely this!!! DO NOT USE 5x100 for a 5x4" pattern. It does not fit. 1.6mm is a big deal when it comes to the entire pattern, it will put additional side loads on the studs that they were not designed for. Even if the holes in the rim are large enough to account for the difference (ie, the rim physically slides on the lugs) it will not allow the rim to be properly centered on the hub. The difference in the pattern will put the lug against one side of the lug hole on one lug, and the other side on another and so forth, so that the rim is no longer centered properly on the hub. And of course, when you tighten the tapered lug nuts it will side load the studs when it tries to force the lug studs into the center of the hole. People have done this, some have even drilled the lug holes in the rims out larger. Some folks will tell you its "ok", but there have been lug failures when this is done.
If you've got a 5x4" pattern, you need to use 5x4" pattern rims, convert to BBP, or run a conversion adapter/spacer with rims that have a deeper backspace to account for the spacer.
