Since I am out of warranty I did swap out the rear diff cover. I am glad I did because when I dropped the stock one almost no fluid came out.
I don't know if they will void any warranties for something like this but I guess it depends on the dealer. I had this cover on when they performed the recall on my truck.
I love it. Has a magnetic dipstick as well as a drain plug so I don't have to take it off or stick some tube down there and attempt to drain fluid.
As stated above I plan to do the transmission pan eventually.