My e-revo brushless edition build

couple questions....I am installing lst diffs in my revo....I know the lst diffs have a different gear ratio than the traxxas diffs but are there different gear ratio sets that can go in the lst diffs or are they all the same regardless of what the diff came out of? I ask because the diffs I bought are in a silver case while most I've seen are in a blue case and I remember reading a comment from someone that implied there are different ring/pinion gear sets for the lst diffs.

Also, I have been running a 54/20 gear ratio on my revo with the stock diffs.....will going to a 24 tooth pinion be slower or faster than what I'm used too on it with the lst diffs?