Anyone upgrade the internals of a 4R70W yet?

Mine is starting to slip after 60k miles, but will be covered under warranty (parts and labor minus $50.00 deductable). While the trans is opened up, I was thinking about upgrading the friction plates to something better (if it's recommended and makes sense).

I remember a while ago a guy named Marc99GT installed some raybestos (think that was the brand) plates/clutches in his 4R when he did a turbo upgrade, but he sold the car and haven't read of many people upgrading since him.

Anyone done any internal upgrades?