The rebuild kits are the same for all the 8.8's, the only difference that I know of is the differential on the IRS has grooves machined in it for the halfshafts where as the solid uses C-clips. You can actually set up your own gears by using the master housing dimension (MHD) which is a fixed length from the back of the pinion gear to the axle centerline. Since Ford set our gears up this way from the factory we do not need a pinon depth guage to measure the pinion depth. You will still need a few specialty tools and you have to use Ford Motorsprt/SVO gears to do it. I just found out about this process earlier in the week and I can point you in the right direction send me a PM if you want to know more.