[kyleb]

I would use the arms but don't bother with the original axles. I know a number of people who have snapped them. Use the ends and have the axle made by spicer or a tail shaft specialist to the correct length using the heavier unis and then you can forget about them.
The problem with the JAG rear is availability of new parts. I rebuilt mine with a new crownwheel and pinion from Dennis whelch motorsports in the U.K and fitted an Auburg gear LSD clutch pack. It is now pretty much indestructible but took some working out.
That's not to say you can't get a good second hand unit that will last ages, just food for thought in regards to longevity and how much power you will put through it.