Personally, I have two major issues with the retrofit...
1. Programming: there's absolutely no assurance that even installing the components the dealer will be able to make the car software accept a P/N that was never part of its possible list/Vehicle order. This is completely different from retrofitting the iDrive to a non-iDrive car of the same model year.
It has been already proven that an iDrive retrofit is possible, but it has been also proven that it is possible only if the parts retrofitted match an expected Vehicle Order and only if that Vehicle Order can be modified by BMW/dealer itself to accept the new specific parts/features. I just can't see myself paying $160 an hour to a dealer to just experiment in programming these parts without any assurance that they will be successful.
2. Core charges: there is a $1000 core charge ($500 for the computer/HDD, $500 for the screen) in this retrofit/swap. The economy is not well at all to just dump $1000 in this type of charge with no assurance of even working - and again, on top of programming charges. Now, if that core charge somehow get eliminated then we are talking about a total of around $2200 in parts for a swap of a existing iDrive -a complete retrofit in a non-iDrive vehicle will be more than $3500 in brand new parts, plus major labor costs.
With the current sharp drop in prices and too sweet special offers for MY2009 models, $3200-$4500 (including the core charge but not labor costs) can help some in just trade in/sell your current pre-2009 car and get a 2009 with the new iDrive, as long as you are not upside down with your trade.
These two issues simply need to be solved -either by BMW itself with a proper/official swap TSB and by eliminating the core charge or by just somebody else with money and time to burn that performs this swap/retrofit- for me to go ahead and do it. However, definitely I will be doing the new iDrive controller swap as soon as the shifter trim is finally available for ordering from BMW. For some internal reason, no MY2009 shifter trims are available yet to order from any US BMW dealer right now.
Another thing that can help is to just wait until MY2009 iDrive parts are available used, at a considerably lower cost than new (especially the $1500 LCD screen). At the end, that's what I will be doing...