You can get the teraflex coil spring spacers from 3/4" lift
to 2", if you go with 2" you probally need to upgrade the
shocks, the spacers are about $25 for each corner. With
the 2" you should not have any problems with 31 10.50's.
If you get over 2" you probally going to run in to trouble
with the driveshaft. You will see SYE mentioned on this
site, its a conversion done on your transfercase to keep
the driveshaft from falling out.( slip yoke eliminator).
This will only become a problem if you get over the 2".