[ctuna]

Base system upgrades for sound quality

Base System Upgrades
http://www.e90post.com/forums/showthread.php?t=445266
http://www.1addicts.com/forums/showthread.php?t=634957
http://f30.bimmerpost.com/forums/sho....php?t=1003810
http://www.e90post.com/forums/showthread.php?t=822366
http://www.e90post.com/forums/showthread.php?t=581379
http://www.e90post.com/forums/showthread.php?t=451941
http://www.e90post.com/forums/showthread.php?t=540954
http://www.e90post.com/forums/showth...ghlight=Dotech
http://www.e90post.com/forums/showthread.php?t=495855
http://www.e90post.com/forums/showthread.php?t=494299
http://www.diymobileaudio.com/forum/...morel-jbl.html
http://www.e90post.com/forums/showth...ht=amp+upgrade
http://www.bimmerfest.com/forums/sho...d.php?t=550771
http://www.e90post.com/forums/showth...1#post16679904
http://www.e90post.com/forums/attach...1&d=1411521234
http://www.e90post.com/forums/showthread.php?t=1378833
base system wiring pre/post 3/09
http://www.e90post.com/forums/attach...1&d=1411521234
https://www.google.com/url?sa=t&rct=...tDpLJPcGkw_ui_
http://www.monsteraudiodesign.co.uk/
http://www.e90post.com/forums/showth...1#post16679904

Head unit upgrades for features
head unit
beware of side effects
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showthread.php?t=1457320
http://www.e90post.com/forums/showthread.php?t=1036190
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.janus-design.net/english/
http://www.e90post.com/forums/showthread.php?t=355089
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...light=retrofit
http://www.e90post.com/forums/showthread.php?t=993447
http://www.e90post.com/forums/showthread.php?t=1016187
https://www.bmwgm5.com/Logic7_E90_91_92_93.htm
http://www.e90post.com/forums/showth...hlight=dynavin

The alpine upgrade is not much of an upgrade.