i've done this mod a long time ago, so i've got some experience with this one. if you use anything but flm cvds, the mips will snap like twigs right at the cups. also, if you do this mod, you can rip the planetaries to pieces almost every run because they are not meant to operate with the sheer weight of the wheel/tires. you can counteract that by loosening the slipper, but it will smoke to the point of actually starting to burn if the slipper isn't locked....again the rusty slipper is not meant to function with tires that big.
here's the only combo i found that worked:
FLM cvds with flm's new adapters so they fit the 6mm axle
a locked diff (either get the spool diff sold from HR or fill the inside with JB weld)
lock down the slipper as hard as you can and then back it up with another nut on the shaft. i also had to go to e-maxx black spriings for better suspension. here's an early picture of it:
hope that helps. let me know if i can be of any more assistence.
here's a cool one too:
sure made my stampede look itty bitty LOL