Current most popular solution is
Helix 82dsp with a set of aftermarket speakers (3 way set)from
Jehnert , Gladen or MB Quarrt if you are on a budget.
Get the entire kit from places like Bimmertech, Unexpected Crealions
or MusicarNW. Bimmertech kit comes with a tune and they can
reprogram the output of the Head Unit/idrive to Hi Fi .
since this is a new package I don't know what it costs.
Lower Cost alternative is
http://www.e90post.com/forums/attach...1&d=1411521234
amps and speakers may vary but this is the proven solution.
Base System Upgrades
http://www.e90post.com/forums/showthread.php?t=445266
http://www.monsteraudiodesign.co.uk/
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/showth...1#post16679904
No reason to do an OEM upgrade all of the above is better.
Since you are somewhat close to Unexpected Creations you might want
to see what they can do for you.
If I was doing the Helix 82dsp which is remarked by all of the above
plus Bavsound I would tend to buy it from Bimmertech as I think
the Tech support might be better or if I was looking for a total install
Unexpected Creations.