Found this old thread which has some useful info, too. It’s not as simple as just dropping in a new 6x9 which is only a 2-ohm driver, but there are options.
https://bmwi.bimmerpost.com/forums/s...1304784&page=3
__________________
'17 i8 Protonic Red Edition; '17 “30 Jahre” M3
'90 Z1 Red w/red/black leather, GC coilovers, Alpina Dynamic DS-02
'91 850i Mauritius Blue/Black, BBS RS-GT
'85 M635CSi Alpine w/buffalo; '03 M3 Conv, Imola
‘85 323i Baur; ‘02 X5 4.6is Estoril; ‘95 Racing Dynamics K30.4