"Ultimate Edition"

Honestly I'm quite baffled by it, I have never seen that used as name for a package or trim on Mercury's website or brochures, however I see it on almost all (maybe ALL) late model GM's. You can check their website if you want, see if it's some sort of option package, this paticular one does come with much more than the basic standard equipment, may very well be a package.

http://www.mercuryvehicles.com/grandmarquis/