I own an 88 CRX si that I autocross and rallycross. After we bought the car last year we took it to the alignment shop to see where the alignment was and to ask around about where it should be. One of the main things people said was that our caster being at .8º on the left and .4º on the right wasn't anywhere close to what we want. The shop said we couldn't have the caster changed with stock equipment so we didn't worry about spending money to change it. 10 days after getting the original numbers we took the car in to get it aligned and didn't notice the caster had changed to 1º on the left. About a month later we installed adjustable UCA and had the car aligned once again. This time the caster read -.8º on the left and -1.5º on the right. We took the car in again last week after changing out a half shaft to make sure the numbers were still where we wanted them. Finally I noticed something when the caster was -.9º on the left and -1.9º on the right. I've checked the nuts at the end of the radius arms and they're torqued to 32lbs like our manual says. The only other explanation I've come across here is sub-frame damage but not much explanation on how to check for it. Does the slight change in caster over time sound like sub-frame damage?