Interesting... I remember it being $54K.
I guess the AWD upgrade has changed a number of times from $5K to $4K to $6K... now back to $5K
Yep, quite a few AWD price changes. You even missed one, it went from $4k to $5k before going up to $6k. $6k was always crazy as AWD as an option on the S and X was $5k.
The only reason they upped to $6k (my theory) is to push demand to the non-AWD version to more efficiently use the production lines. When that didn't work they created the MR non-AWD to further increase demand for non-AWD models.