Step by step:
1. what are the shock part numbers front and rear? find those, then look up the compressed shock length with google (or measure it yourself).
2. Now measure how much bumpstop extension was installed with your lift.
3. Now, for every increase in shock length over stock you need a proportional increase in bumpstop extension to prevent the shocks from overcompressing. Stock rear shocks are 12.25" compressed length, stock front shocks are 13" compressed length. So, if your new front shocks are 14.5" compressed length, you need about 1.5" bumpstop extension. For reference, with a BB, the rear bumpstop extensions need to be the same height as the spacer...so this will likely be the determining factor in your case.