kyle,
The 'driveshaft in a 944 is called a torque tube. It's basically a casing that has a shaft in it that is spun on bearings. I had to replace mine about 2 years ago on my '86. In my case the housing cracked and was making hellacious noises whenever I accelerated. New remanufactured ones are about $3K, but you can probally pick up a used one for around $200-400. Look in the classifieds on www.rennlist.com, or one of the dozen or so places that specialize in used Porsche parts. Or you can call Eurosport in Va Beach and they probably have one sitting in the back of their place with all of the other shit that they have there. Hope this helps and good luck with the repair.