Boxterfahrer, you are not alone. I had a similar experience, I just got lucky.
Several months ago I decided to order the LN Engineering kit, to retrofit my IMS (Inter Mediate Shaft) bearing (single row) with the LN Engineering bearing and IMS flange (cover) in my 2002 911. This way I wouldn’t have to worry about the IMS problem as much.
Working with Jack stands in my garage was ok. I purchased some 6 ton jacks from Harbor Freight for the rear of the car and regular car ramps (installed sideways) for the front. Finally, I purchased a transmission puller adaptor for my 3.5 ton jack from Autozone and I was all set. Pulling the transmission was uneventful (that thing is heavy), removing the pressure plate, clutch and flywheel was also straight forward. I then loosened the two chain tensioners (the Crank-IMS one and the IMS-Cam one, on the transmission side of the engine). I left the tensioner on the opposite side alone, as this would do little to loosen the tension on the IMS bearing area. I did not remove the tensioners completely, as I did not want to mess up timing. Removing the IMS flange at this point was easy, however, as expected, I found the IMS shifted to the right and up a bit, about ¼ inch. I proceeded to remove the IMS bearing with the LN Engineering supplied puller, and I then installed the new LN Engineering bearing (with the LN Engineering supplied tool). Next, I had to install the IMS flange, which was tricky, since, without removing the tensioners completely, the IMS was still way off center. Well, I noticed that Porsche was selling the alignment tool. Since that alignment tool would no longer work for me (due to the fact that the new IMS bearing stud was upgraded to a thicker one and the thread would not fit the tool), I drove down to Home Depot and purchased $8 worth of metal peaces and the alignment was done without any problems at all – the new LN Engineering IMS flange was installed.
[attachment=18648:IMS.JPG
Here is where my nightmare almost came to light: LN Engineering mentioned that the new IMS flange may interfere with the flywheel. To test this, I installed the flywheel and proceeded to crank the engine by hand. As soon as I cranked the engine, I felt something like chain skipping across teeth. It is at this precise moment that I realized what may have happened – I forgot to tighten the two tensioners! GAME OVER. I immediately fainted and, as I came to, I was sure that the timing was messed up. I quickly tensioned the two tensioners and proceeded to crank the engine by hand some more, expecting, at any moment, to have the valve hit the piston. To my surprise, however, the engine still turned and the chain skipping across teeth feeling went away. As I turned the engine some more, a full 360 deg. the chain skipping on teeth came back. I was puzzled, as the symptoms were there for 180 deg and disappeared for the other 180 deg. Finally, I remembered that LN Engineering did mention that the flywheel may interfere with the IMS flange. I immediately removed the flywheel and the chain skipping across teeth feeling went away completely. I just had to grind a little spot on the IMS flange and the interference went away. I re-assembled everything and, knock on wood and a prayer, the car started. Thus, I realize how lucky I was – one just has to pay attention 100% at all times, think things through and not get too eager.