Good input here!

I'm not aware of any differences in alternators, though many run without the ducting attached without trouble.

A few other thoughts:
-Make sure you remove the charcoal canister in the LF fender and vent that line somewhere safe
-Get a good, lightweight battery
-Replace the fiberglass roof piece with an aluminum sheet.
-Since you have a late car, you can remove the rear spare tire well (be careful of the gas tank!). I lost 18lbs doing this here: http://www.944spec.org/944SPEC/forum/race-car-build/2589-budget-build-944-spec-racecar-updated-21709?limit=6&start=30
-I'd remove the fuse panel and as a wiring as a whole (sparing only the engine harness). There are some threads with schematics here. This will lose over 30 lbs! You might have to add in a few things for the HVAC system.
-Use a good lightweight battery, and fab your own aluminum tie down.
-For the exhaust, run a short pipe that terminates just ahead of the rear torsion tube, and put in bullet muffler (I use a Hushpower that makes it pretty civil). If you want to be ambitious, you could put a flange on it, and bolt on a straight pipe for the track to save another few pounds.
-Pay attention to the weight of the hardware you put on - Tarett antisway bars and hollow torsion bars save a bit of weight vs. other options. Use aluminum seat mounts, and no sliders.
-Make sure you get rid of all the sunroof motor, and hardware.
-Consider making your cage out of 1.75 x .095 material - it's lighter than 1.5 x .120 tubing.
-Definitely gut the doors aggressively. I love the 911 R style windows!
-Run Cookie Cutter wheels (slightly lighter than phone dials)
-Unbolt the factory tie down eyes on the front, underside of the front frame horns - you don;t need them, and they are beefy.
-Make the wiper motor a plug-in option for when you need it, remove it when you dont.
-Use a manual steering rack, or at least depower the power one, and remove all the associated hardware, cooling lines, etc.
-Lighten your dash a bunch for cheap the Ken Frey way: http://www.944spec.org/944SPEC/forum/race-car-build/9155-new-car-build?limit=6&start=18. Others have made lightweight molds of the dash.
-Lightweight steering wheel:
Just kidding!

That's a good start, I'll see what I else I can remember...

Thanks for all the input guys!

Doc, the dash thread helped as I think I will use the stock shell and swiss cheese it then cover it in speaker cloth. I plan to use the stock gauge cluster since I doubt aftermarket gauges will be lighter plus it it there.

The rear tire bin will be cut soon, thanks for the info.

The window lifts worked out nice. I used 2" nylon strapping and heavy duty snaps from Tandy Leather. The strap is fed under the metal window lift support and secured with a spring pin that I slid over the strap and the melted end is larger so it will not budge. The snaps/strap are lined up with an existing rolled flange on the inner door so the strap has a nice surface to be pull against. I set snaps at full up, full down (just off the bottom), middle and just cracked open. I works well and the windows slide out completely for race day in 10 sec.