for whats its worth I just put a new adj trac bar and steering stabilizer on. To be honest I didn't notice 'that' big of a difference on the road, granted if your doing a lot of cornering at speed you may like the feel better. Everyday driving I don't notice anything great.
As for the disco's, well if you offroad a lot and enjoy the extra flex/articulation they may provide I would say go with them.
I am new to this sport so my 2cents isn't worth what others may be... but if my axle was centered ok without the adj trac bar, I would have went with disco's.
On a side note, I had one hell of a time removing my old steering stabilizer, I had to go out and buy a pickle fork to get the bolt holding it into the draglink out... SOB that it was it come sout with force so strap that stabilizer to the draglink if you want to remove that bolt... look out.