I use the snap in adapter. It is expensive but I found one on eBay for around $150.
I don't use it for video, at least not yet.
I use it for the alternative iPOD interface, antenna boost and charging.
I also like using the BMW Apps Internet music channels and streaming Pandora although this can be done with just the white cable.
The key to the adapter is finding an iPhone case that can be easily removed/installed.
2008 VW GTi