If you have an L7 system you can't replace the head unit without
a new wiring system and amp because the BMW system uses a
fiber optic connection to the amp that is very non standard. There also can be side effects from the other devices that connect to the Head unit.
Sos will cause a permanent error to be displayed and PDC will cease to work with most head units if you have it.
Also the BMW dealership will not be able to do software updates
and some repairs without the original head unit mounted. Some
people mount the original head unit in the trunk for this reason.
Most stereo shops can be kind of Brain Dead about this stuff.(Yes they really are about 95 %)
You do not want to put a Aftermarket Head unit in a BMW with idrive/Nav it's just not done.
Your idrive will not work anymore. If you must upgrade it put in a BMW NBT system.
Start searching for NBT upgrade and also look
That will give you A2DP and all kind of Internet stuff.
What will you do with the big dead OEM idrive/nav screen in the middle of the dash?
http://www.e90post.com/forums/forumdisplay.php?f=122
BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://www.e90post.com/forums/attach...1&d=1209780865
electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...4&d=1278871872
You will be in for costly trouble if you don't do your homework
and really know what you are doing.
If you live in NJ to see Six Speed Coupe at Unexpected Creations he knows BMW's
He is the only one that has done one of these but it is almost never done on a idrive/nav.