I was mulling over a CIC retrofit which would probably cost me around £1200 or a CD Changer and better speakers which would cost me around £600 and in the end I decided for the latter because not only would I save a hell of a lot of money, I realised; why the hell do I need a new iDrive for?! I just want to listen to good music and drive my amazing car I waited ages to buy! and guess what, the music sounds great and the car's even better
PS. All your family/friends/girlfriends just want to enjoy the ride too. They don't care if you changed the iDrive, they're amazed you even have an onboard computer! "Yeahhh, I changed the CCC to a CIC
...huh?!" = If you have to explain something to someone then it's probably not 'cool' anyway.
...Having said that, it's all about self satisfaction, you upgrade your car however the hell you like and as long as you're happy then that's all that matter.