I am needing a new rear diff soon (mine is making noises). I have a MY02 STI with a stock Suretrac diff in the front, a cusco tarmac gear (35/65 split) open diff in the center, and a 2 year old STI helical diff in the rear.

The rear is starting to make noises (I'm pretty sure it's not happy being mostly RWD after two years of driving) this is a street car so I'm looking for something with lower maintenance intervals, and nice slow progressive lock up.

Any suggestions? If I can I may try the torsen again (no aftermarket torsen) and run a thicker fluid, but I'm not sure that will help. I'm considering going back to a suretrac as well, but they are prone to wear. Cusco RS is okay it seems but apparently lots of fluid changes.

Any suggestions?