Here's the consensus as found in the aftersales training pdf (p.39):
"In order to provide an enhanced sporting
character and more hold, the seat cushions
and backrests in European vehicles have been
further developed. In US vehicles, only the
front seat backrests have been revised. The
seat upholstery installed in US vehicles is the
same as that used on the E92 series-model
sport seat."
Best regards, south