IIRC, the 33x10.50's you have have the continuous center chevron, which is alleged to be better for mud...the 32x10.50's have the split chevrons, for more of a general Swamper mud/rocks/etc. approach. Note that is word of mouth, not any sort of statement from Interco. I don't know about the 31's...
Here's a thread from JU that talks about this a bit, and TSL Radials in general. Funny to see the differing opinions on the tires, too...funny how most of the people who don't like them...don't have them.
http://jeepsunlimited.com/ubb/Forum20/HTML/003660.html