Man, I've posted this quite a few times, I have done the swap, and here is the EXACT differences.
The IRS Trac-Lock has a BEVEL in the gear, not a slot. It is there to make it so that you can take the halfshafts out of the car without dissassembling the entire rear. You can put the solid axle Trac-Lock in the IRS with NO RETENTION PROBLEMS, because the circlip will slide all the way past the gears, and expand. Where you run into a problem is when you have to take a halfshaft out for some reason. Without the bevel, the circlip will not compress itself and slide out, which leaves you 2 options, pry hard enough to break the circlip (not really an option for me!) or take the cover off the rear, and pop the circlip off with a pick, and then pull the halfshaft out. There are NO safety issues with running a solid axle trac-lock in a IRS rear, and it will not allow the halfshafts to slide around.
Another option is to order the side gears from Dan Newman, he found the part numbers for Ozzman, and swap them out, no big deal, and I believe they cost $70.