Hopefully you have already read through some of the "I messed up using set screw" and "Shaft is off center." threads. I was fortunate enough to have a bad engine to mess up on, then do it right on my good engine (Pinned at TDC and no set screws).
This is a good guide with pictures. (I think it was made by another Forum member.):
porsche service boxster ims bearing repair install 986 diy tutorial Intermediate Shaft Bearing Replacement and Upgrade (IMS) Step by Step Replacement Guide - MIKE'S SPECIALTY AUTOMOTIVE SERVICE****Specializing in Porsche