My 2013 X1 has the 4 attachment points in the boot so the spare storage bags should be compatible. BavAuto has a branded bag that it is a bit less expensive than the Genuine BMW bag):
http://www.bavauto.com/fland.asp?par...FYp_QgodW2cAFg
http://www.bavauto.com/fland.asp?par...FQ_hQgodG1MAdw