Not much else I can add that hasn't already been said. The Durga is an awesome car once it is dialed in correctly.
A decent inexpensive set of ceramic nitride diff balls can be bought from JAAD Racing (each set of 12 balls will replace the balls for one diff) -
http://www.precisionrc.com/nv/car/product/...roduct_id=54309
Here is a link for the ceramic nitride thrust bearings as well -
http://www.precisionrc.com/nv/car/product/...roduct_id=53980
These are the ones I have been using for months on the track. They have been bulletproof and are still perfect after a few diff inspections.
Hope this helps.