upgrading speakers would not make a lot of difference.
However if you still want to experiment, there is no harm in trying vibe slick co-axials.
RETROFITS: LCI Conversion - LCI Xenons - LCI Tail lights - Memory heated seats -
Folding mirrors with auto-dip - Rear PDC - CIC with DAB Plus - Combox - 6FL - 6NF
- 6NR - BMW live & Internet
MODS: Eibach Sportsline - AluFelgens CS7 - JBL MS-8 - Gladen components - SWS-8