Check out the products by Brodit. They make mounting points for any car for any device.
There's a 986 specific mount here:
ProClip****Porsche****Boxster****1999****852428****|****Brodit
My car had the telephone module preparation, so I have the bulge for the handset on the right of the center console. It's flat, so I got their simplest screw-down plate and a phone-specific holder.