How do I determine what version my 2003 Mercury Mountaineer is?

*Correct tire size* is displayed on a sticker / decal - located on drivers door jam.

see other answer. also there is not a "per say" luxury model of the 03 Mountaineer,only a Sport Utility 4DR or Premier Sport Utility 4DR and there were 2 different size wheels/tires for both sub-models>> Mercury equips your vehicle with more than one possible size during production,either the 245/70-16 or 245/65-17,as pushrod stated,it's on the door jamb label....