Ordered and installed. The liner arrived quickly and in perfect condition, not folded.
When I got my 135i, I ordered the OEM liner for it. This X1 liner from Bimmerfox is more like the older style liners - that is, a thicker, cloth covered liner, compared to the 135i OEM liner which seems to be black painted rigid foam.
I was a little concerned about the fasteners accompanying this liner, they seemed a little less substantial than the OEM fasteners on the 135i. However, a quick test using a trim pry tool showed that these fasteners aren't going anywhere once installed.
All-in-all, I would certainly recommend this liner for the X1.