For this retrofit there are no installation instructions. To be installed by skilled personnel only, best by a BMW partner. BMW is unable to accept any responsibility for operating failures and damages resulting from incorrect installation. For retrofitting, the roofliner must be removed and cut at the points marked on the back. Refer to repair instruction REP-51 44 013. Installation time approx. 8.0 hours, which may vary depending on the condition of the vehicle and the equipment in it.