Help me save some $$$$$

You can go buy a brand new one for $699-799 from ford with your choice of gears. I bought a new one form my 94gt last summer from mustangs unlimited for $750. Took me the one day to install it myself.
 
You can have all the bearings and a gear change for half that. The differential doesn't need to be rebuilt if you only have a bad bearing. I had a carrier bearing go bad and had that along with the pinion bearings and gears done for $595. Call around to some performance shops and let them do it. Ford dealer will rip you off.