XLine - Silver/Alum exterior trim, wood or copper interior bits, tobacco interior
Sport - gloss black exterior trim, gloss black or alum (+$500) interior trim, sport steering wheel and seats, coral red interior
What's most important to you, as the options I've listed are exclusive to each line. Also the 18" wheels are different on the two lines as you know.
I opted for the sport, as the red interior, sport wheel and seats were must haves for me, plus I like the OEM gunmetal wheel that comes with the sport model. I was also considering the Msport, but the paddle shifter issue and lack of A/S tires
(until now) were deal-breakers for me. Perfectly happy w/Sport as I wanted LeMans blue, an exclusive color on Msport, while the wife wanted Alpine White regardless, so no point in wasting an extra $1K.
You need to test drive cars w/wo the Assisted Steering to determine which one you like best, as its totally subjective. I'm perfectly content w/o the servo.