Let me start with I am new to even the idea of putting an IRS in a vehicle that has a solid axle right now, so I am just starting to do research and have to learn even the basics.

Application:
4.8 LS swapped regular cab short bed 98 S-10 with a NV3500 5 spd.  I will eventually put a T56 in it, but I have the 5 spd on hand.  The motor is completely stock for now.  The truck will be a spirited daily driver with some attempts at running autocross.

I recently started working at a shop that works on Jaguars and Land Rovers and I have been drooling over the IRS in the Jags.  I realize the 94 XJ6 IRS is not as self contained as a lot of the other units, and not very popular with hot rod guys for that reason, but that part doesn't really concern me.  My concerns are more in the differential and the power they can handle.  I am also wondering if swapping to a different gear ratio would even be a possibility.  Are the differentials similar to the other more self contained units?  I am interested in this setup because we have a 94 XJ6 parts car with a complete setup in it, and just wanting to make sure I don't go through the hassle of putting it in, only to have it blow up or be stuck with a really high gear ratio.

Thanks