I just talked to a guy in the parts dept at the dealer where I purchased the car. He had never heard of XL-18. I'm really not sure if I need to just buy some of this stuff from Ford or go through the dealer. I did get him to verify the TSB on the lower control arms, so I've got an appointment next week to get them looked at.
Buddy of mine works in the service aisle at a pretty good sized Ford/Lincoln store around here (Metro Detroit). They don't have it in stock, there isn't a dealer in MI with it in stock, 3 of their regional distribution warehouses don't have it either. He found 1 dealer 252 miles away with ONE bottle on hand. Other's were scattered throughout the midwest. I'm guessing it's popular stuff.