I thought about doing this, but once it mentioned having to buy an 6M extension since I have navigation that I would have to run the length of the vehicle just for it to work - I decided against it. I am not about to gut the interior to upgrade my head unit. It's just not plug & play if you have standard navigation from factory. One perk of business radio is that it's easy to upgrade to aftermarket head units as they are truly plug & play. I believe all 4.8iS came standard with navigation?

I have this issue with my 2002 M3 as well since it came with navigation. I desperately want a modern head unit or at least BT for that matter in my M3 but it's just not possible without gutting. I could go FM transmitters (which blow) or GROMM which is probably my best option without taking out the interior. I have already retrofit aux with wireless BT in my 4.8iS and i'll just leave it as-is.

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2004 BMW M3 Individual
2009 BMW E70 X5 35d
2011 BMW E70 X5 35d - Totaled
2009 BMW M3 E90 - SOLD
2006 E53 X5 4.8iS - SOLD
2002 E46 M3 Convertible - SOLD
2006 E46 M3 ZCP - SOLD
2011 E70 X5 35d - SOLD
2000 E39 ///M5 - SOLD
2003 E53 X5 4.6iS - SOLD
2006 E83 X3 3.0i MSport - SOLD
2000 E46 323Ci - SOLD