I have a 4.5 inch RC lift on my 1998 XJ (adjustable upper and lower control arms). After the lift I had an alignment shop do an alignment. Last week I installed some control arm drop brackets, also from RC. When I was installing the brackets I realized there where no shims behind my lower control arm. I made sure the arms were to what the directions said. When I got the brackets on I had a shop do the alignment. My caster is at -2.9 degrees. I think spec is 5-8 degrees. The guy at the shop said adding shims could note make up this difference to get my caster to spec. He said I need to lengthen the lower arms and shorten the upper arms. Any idea how much longer I should make the lower and how much shorter I should make the uppers so I can get close enough for shims to get me to spec?