I just replaced the windshield on my 944. Had a similar experience with a rock being thrown up on the expressway by a 18-wheeler. I ended up buying the windshield with no antenna as it was over $150 cheaper! I have no radio reception right now, but plan to add an aftermarket roof mounted antenna, similar to the 968's which was placed directly infront of the rear hatch. I hardly use the radio as i have an MP3 deck, but want it mostly for AM reception so i can listen to the news in the event anything big is going on.
http://www.rennbay.com/amplified-fuba-bataflexd-968-type-radio-antenna-p-50.html
Even after $60 for the antenna, that still puts me $90 ahead on the other windshield and gives me better radio reception.
When you do replace your windshield, if you plan on getting the model without an antenna, make sure you tell whoever you are ordering from to verify the windshield is for a late model car. The early style windshields were not flush mounted and leave about a .5 inch gap on each side. Most installers will just more glue and a larger gasket...which is asking for leaks.