If you just want to lower the rear to make it more level, you have to replace the lift blocks. I don't know about the '00's, but they may be the same as my '02 which had 4 3/4" blocks. I replaced them with 3" blocks and now it sits level when towing my trailer. If you go more than about a 2" drop you have to consider other things like pinion angle, shock length, front wheel alignment and headlight aiming. Also, don't forget shorter U-bolts. Now, lowering the front is another story. Personally, I wouldn't recommend it as it already has a short suspension travel and being a 4x4, you would have trouble with alignment due to the track bar.
Jim