My understanding is that the "sport" has the utilitarian interior, and the "regular" has the foam/vinyl lined interior, with some other upgrades. "Hull liner and foam back vinyl" in the regular. (even though both seem to say the same thing on the Web site. I personally like the utilitarian interior--the foam lined vinyl tends to delaminate, and harbor mold in Florida. (from my experience) There are hull liner materials, which are more resistant to these elements which go with heat and high humidity.