Originally posted by TC3er
I would go with the IRS one, or you can just take a regular diff and take out the balls and tighten the screw all the way down.
You can leave the balls in when you try this just assemble it dry with old parts then shimming is easier.. In case of a hard crash its easier on the outdrives to have some give. I put one together with epoxy to see how it worked and broke an outdrive and a set of gears the first crash it was in. I only tried it once after that without the epoxy but it didnt break parts.