STX, Lariat, FX4, XLT
#3
My Guess
Here is my guess. The TX is for trucks and the S is for Sport or Sound. That makes it either Sport Truck or Sounds Truck. Sport probably makes more sense since the STX designation has been around for a while (on older Rangers), but I include Sound because the 03 STX package feature was a special Kenwood sound system and you can get the 04 with all the sound options up to Audiophile (which isn't available on the higher model XLT).