I did two DIYs in the DIY section on tranny and rear diff oil changes. I put the appropriate Redline products in each. I did the rear diff first but didn't notice any difference really (not sure I would really notice anything). The rear diff oil was NASTY, so that alone made the change worth it. After I changed the tranny oil (which looked pristine), the car shifts much much smoother. With a cold start, it shifted like a warm transmission instead of the clunky, stiff shifts you normally get before the car warms up. Definitely worth changing out both oils. I did it at 3k miles. Changed the motor oil to Redline at 5k.
DIY: Transmission Oil Change
DIY: Rear Differential Oil Change