As for helping your stock unit last longer, here are some ideas -
First, change out the stock pan for a Mag Hytec double deep. It will add 7 quarts to your capacity.
Second, replace the ATF cooler with something bigger.
Third, a valve body modification wouldn't be a bad idea at all, either a whole valve body or the parts to modify it yourself. not a hard thing for you to do if you know your way around your toolbox.
Fourth, fill it with a quality synthetic oil. Obviously, I recommend Amsoil. I use it in my race truck's auto and it is very good, durable fluid. Had a lot of good luck with it.
I think all of these plus the Superchips will help you get better control over the trans and help to address some of the things that typically take out transmsissions early.