I am always wary of buying new things until they are in the rule book.
Careful Dennis... there was no update to the wheel or tire weight rule published since March of 2010, so the most recent rule is:
75. WHEELS: Any type of automotive steel wheel that has a 13” diameter, a 7” width and the offset of 3” to 3 1/4” from back rim edge to back of wheel center is permitted. The minimum weight of a BF Goodrich tire and wheel must be at least 36.0 pounds without additional weights. The minimum weight of a Federal tire must be at least 31.0 pounds. All wheel weights must be covered with duct tape. Bleeder or relief valves are not permitted in the wheels. INEX approved (and marked) beadlock wheel will be allowed to be used on the right rear corner ONLY.
My cars are both underweight as it is with the "old" 18lb wheels on them.
...which, I believe, makes every wheel that has been sold since the new lightweight wheel became available illegal per the latest publication of the rule book. I'm sure they will update the rule book for 2012, but as of right now just about everyone is illegal, even the dirt guys because the AR is much lighter than the BFG was...just a technicality, but I don't want to see anyone get burned.
I also wonder about possible reliability issues of the lighter wheels on dirt with some of the rougher tracks, and wonder if having the 20lb beadlock on the RR and a 13 lb wheel on the left rear will be an issue.
Either way, Bassett only makes the 13lb wheel now, so you don't have a choice if you want Bassett.