I though tthey we over £600??
£240 seems a bit hopeful
By chance I fitted my own this weekend. Not Gruppe M but someone sent me one FOC that they had moulded in CF themsleves, sold the Z4 and had no use for it. Took an hour to get it all sorted but really neat how it scoops the air from behind the grille and directs it into the filter where the OEM U cup is removed