When doing replacement or upgrading on 1998 – 2011 BMW 323is 323Ci 323i capsule halogen headlamps HID with, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight 2000 H7
High Beam Headlight 2000 H7
Front Fog Light 2000 9006
Back Up Light 2000 1156
Brake 2000 1156
Dome Light 2000 DE3423
Front Side Marker 2000 12961
Front Turn Signal 2000 P21W
License Plate 2000 12844
Parking Light 2000 194
Rear Side Marker 2000 P21/4W
Rear Turn Signal 2000 1156
Tail Light 2000 P21/4W
Glove Box 2000 DE3423
Stepwell 2000 12844
Trunk 2000 6411
Low Beam Headlight 2000 D2S
High Beam Headlight 2000 H7
Front Fog Light 2000 9006
Back Up Light 2000 1156
Brake 2000 1156
Dome Light 2000 DE3423
Front Side Marker 2000 12961
Front Turn Signal 2000 P21W
License Plate 2000 12844
Parking Light 2000 194
Rear Side Marker 2000 P21/4W
Rear Turn Signal 2000 P21W
Tail Light 2000 P21/4W
Glove Box 2000 DE3423
Stepwell 2000 12844
Trunk 2000 6411
Low Beam Headlight 1999 – 2000, 2006 – 2011 H7
High Beam Headlight 1999 – 2000, 2006 – 2011 H7
Front Fog Light 1999 – 2000 9006
2006 – 2011 H11
Back Up Light 1999 – 2000 1156
2006 – 2011 H21W
Brake 1999 – 2000, 2006 – 2011 1156
Dome Light 2006 – 2011 194
1999 – 2000 DE3423
Front Side Marker 1999 – 2000, 2006 – 2011 12961
Front Turn Signal 1999 – 2000 P21W
License Plate 1999 – 2000, 2006 – 2011 12844
Parking Light 2006 – 2011 12961
1999 – 2000 194
Rear Side Marker 1999 – 2000 P21/4W
Rear Turn Signal 1999 – 2000, 2006, 2009 – 2011 1156
2007 – 2008 P21W
Tail Light 1999 – 2000 P21/4W
Front Inner Turn Signal 2006 – 2011 PY21W
Front Outer Turn Signal 2006 – 2011 12396NA
Courtesy 2006 – 2011 12961
Glove Box 1999 – 2000, 2006 – 2011 DE3423
Stepwell 1999 – 2000 12844
Trunk 1999 – 2000, 2006 – 2011 6411
Low Beam Headlight 2006 – 2011 D1S
1999 – 2000 D2S
High Beam Headlight 1999 – 2000, 2006 – 2011 H7
Front Fog Light 1999 – 2000 9006
2006 – 2011 H11
Back Up Light 1999 – 2000 1156
2006 – 2011 H21W
Brake 1999 – 2000, 2006 – 2011 1156
Dome Light 2006 – 2011 194
1999 – 2000 DE3423
Front Side Marker 1999 – 2000, 2006 – 2011 12961
Front Turn Signal 1999 – 2000 P21W
License Plate 1999 – 2000, 2006 – 2011 12844
Parking Light 2006 – 2009, 2011 12961
1999 – 2000, 2010 194
Rear Side Marker 1999 – 2000 P21/4W
Rear Turn Signal 1999 – 2000, 2007 – 2009, 2011 1156
2006, 2010 P21W
Tail Light 1999 – 2000 P21/4W
Front Inner Turn Signal 2006 – 2011 PY21W
Front Outer Turn Signal 2006 – 2011 12396NA
Courtesy 2006 – 2011 12961
Glove Box 1999 – 2000, 2006 – 2011 DE3423
Stepwell 1999 – 2000 12844
Trunk 1999 – 2000, 2006 – 2011 6411
Low Beam Headlight 1998 9006
High Beam Headlight 1998 9005
Front Fog Light 1998 H1
Back Up Light 1998 1156
Brake 1998 1157
Dome Light 1998 578
Front Side Marker 1998 P21/5W
License Plate 1998 12844
Parking Light 1998 12961
Rear Side Marker 1998 1157
Rear Turn Signal 1998 1156
Tail Light 1998 1157
Front Inner Turn Signal 1998 1157
Front Outer Turn Signal 1998 12821
Center High Mount Stop Light 1998 1156
Courtesy 1998 6418
Glove Box 1998 DE3423
Trunk 1998 12844
Low Beam Headlight 1998 – 1999 9006
High Beam Headlight 1998 – 1999 9005
Front Fog Light 1998 – 1999 H1
Back Up Light 1998 – 1999 1156
Brake 1998 – 1999 1157
Dome Light 1998 578
1999 DE3423
Front Side Marker 1998 – 1999 P21/5W
License Plate 1998 – 1999 12844
Parking Light 1998 – 1999 12961
Rear Side Marker 1998 – 1999 1157
Rear Turn Signal 1998 – 1999 1156
Tail Light 1998 – 1999 1157
Front Inner Turn Signal 1998 – 1999 1157
Front Outer Turn Signal 1998 – 1999 12821
Center High Mount Stop Light 1998 – 1999 1156
Courtesy 1998 – 1999 6418
Glove Box 1998 – 1999 DE3423
Trunk 1998 – 1999 12844