Differential output shafts
 

I am thinking of going to the hardened output shafts for my 04. Is this mod a do it yourself installation or are special tool required.

If you are handy, and preferably have a lift to make it easier, you should be fine.
I did mine in about 4-5hrs, being the first time I ever had the diff apart, and I wanted to take my time.
I had a lift, too.
It really helped.
You will need a press to remove the right side shaft, but that is pretty much the only real specialty tool you need, from recollection.
If you do the shafts, do the preload spring washers that place pressure on the diff clutch pack.
I had only about 15k miles on my car, and both OE washers had cracks in them, effectively weakening the preload on the diff clutch pack.

Thanks for the info. I assume the diff does not have to be seperated from the trans? Asfor the clutch pack spring washers, just use OEM replacements?

It has to be pulled back.
Unbolt the upper a-arms and lower shock bolts, pop the axles out, remove(or lower) the k-member, take the right side cover off, and unbolt and pull back the diff.
I did not take mine off all the way.
As you pull it back, the trans output shaft is removed far enough to pull the ring gear/posi unit out.
Just be careful.
Might need another pair of hands to help.

edit-I used the upgraded washers from DTE, they are quite a bit heavier than OE

Thanks again for the reply. Very helpful info. I don't have a lift but will be installing the shafts at the same time as the new clutch.

If you are doing the clutch, you'll have the whole drivetrain down anyway, so you'll be fine.
Good luck.