There should be a plate on your gear housing on both axels that tell you the gear ratio. i have 3.73 and it is a little slower and rarely need 6th gear anymore but it is fine for me.
I bought the 4.25 Zone combo kit
3" suspension lift minus the t-case drop
1.25" Body lift minus the radiator relocation kit
1" motor mount lift
for A few bucks more than the 3" suspension lift, sold the MML and BL and added a couple of washers to drop the t-case and no vibes. Plus I sold the 2 for more than the additional cost I spent on them.
And the person that bought them paid less than the cost new from Zone.
Win for all.