Hello, just saw your inquiry and might be too late. However, if you still need this info, I had my MK4 repaired last year to a master alpine technician in NJ. My MK4 was shot since I mistakenly bought a CCC Map version. It damaged the CPU and the laser DVD reader. Jimmy (tech guy) repaired it in 48 hours. Since then, I dealt with Jimmy on LCD monitor replacement and an MK3 issues on my other vehicle. He does Mercedez nav & radio unit repairs as well.

I actually found him in EBay. Here's one of his posting:

http://www.ebay.com/itm/BMW-DVD-NAVI...94d6a1&vxp=mtr

Hope this helps.