What does 2+2 equal? If Lexus is doing the math, its newest model could be the answer.

Toyota Motor Corp.'s luxury division is finalizing a production version of the LF-LC concept car revealed on the auto show circuit four years ago. Lexus has lacked a 2+2 sports coupe — with two seats in the front and two small ones in back — since its SC models ended production in 2010.

Plugging this hole in the lineup fits with Toyota President Akio Toyoda's vision to transform Lexus from a maker of reliable if staid luxury vehicles into a brand that elicits passion and emotion. Sports coupes also tend to put a premium on reducing weight for better performance, so a production version of LF-LC could justify Lexus's in-house work on the light and strong but expensive carbon fiber used on its $375,000 LFA supercar.