I found custom 986
ProClip works the best. It is designed well, holds the phone securely, looks good, and leaves no permanent marks. No glue, etc.. Cost is about $70+, depending on options. Expensive, but worth it. The rest of the holders I've seen look like junk. Google around for ProClipUSA coupons..
ProClip for 986/Boxster
If my Box wasn't sleeping right now, I'd take a pict. Works great with my single-DIN
Alpine CDE-HD149BT with red illumination. I use it for navigation, music, phone.