The Tera 4:1 is probably the best thing I have done to my jeep. You WILL LOVE the lower 4:1 Low Range. Also if you are getting an entire case with the 4:1 for 750 i'd jump on it. You can easily slide your 2 low in there and then sell your other case to make some of the cash back.
As a matter of fact if you don't buy it let me know and I will buy it.