Ok, so here we go have 99 sport w/ 3" lift. Have had on for about 2.5 years now.... Just rotated tires due to bad coupling of front tires only and now have the driver front tire hitting the back of the fender... Question is did a measurement on the wheel base and found the driver side =100 and pass=100.5 so do I need to buy adjustable arms or just shim the lower driver arm out the 1/2 inch or do I need to get both UCA and LCA

 

A wheelbase difference of 10mm is factory spec.
You can get an alignment 'printout' for free. It will show the thrust angles and everything else. Then determine how to adjust.

http://go.jeep-xj.info/HowtoAlignment.htm

 

What size tires you running ?

 

I've done a little research before doing a DIY alignment and learned that Jeep engineered the .5" advance on the passenger side axle specifically to counter the crown on North American highways. I am at 1" (101" driver/102" passenger) so I've got some work to do.

 

running 31's

 

Thanks for also pointing that out, sometimes folks think I'm off-base when I mention it. There is also a small amount of 'cross caster' built into the axle.
I evened out the wheelbase on my XJ but have not put it on the rack for a free alignment printout. I think the thrust angle will determine if I did the right thing.
I also use the 'stringing' method as part of an overall DIY alignment. Here are good how-to's on it.
http://www.circletrack.com/chassiste...ring_your_car/
http://www.stockcarracing.com/techar...try_stringing/