Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I use a proclip in my 2010 GTI. This is pictured with my 3GS in an otterbox, but my iPhone 4 + Bumper fits fine:

img2992q.jpg

I'm going to look into this. I currently have arkon air vent mount and it not too stable.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.