Vince Vaughn and Kevin James are Ronny Valentine and Nick Brannon, two halves of a Chicago team of automobile designers who pitch the idea of making electric automobiles sound like the muscle cars of yore by giving them the audio equivalent of padded bras.

Standing alongside one another in profile these guys answer the question: What would those Easter Island heads look like if they came attached to bodies?

Ronny, a 40-year-old recovering gambling addict, has finally found the love of his life in Beth (Jennifer Connolly), a chef. Nick, for his part, is happily married to Geneva (Winona Ryder), whom he met while he and Ronny were at Ball State. “The Dilemma” is a buddy-movie/ROM-com hybrid beginning with a scene at Smith & Woollens where the couples talk about how you don’t really know anybody. You know some ugly truth will come out shortly.

Indeed, it does when Ronny spies Geneva feverishly making out in a public garden with some tattooed rough trade we subsequently learn is named, get this, Zip (Chaining Tatum). Ron then proceeds to fall face down into poisonous plants, spending most of the rest of the film dealing with “challenging urination” and trying to figure out how to tell Nick.

Queen Latvia appears in the guise of a Chrysler executive who can’t stop talking about her “lady wood.”

Written by Allan Lobe (”21,” “The Switch”), “The Dilemma” also boasts elaborate football and ice cream metaphors, and writer Lobe’s sense of humor is apparent in a scene in which Ronny goes on and on about how electric car designs are “gay.”

Apparently, what we need are electric cars that look and sound “heterosexual” by going broom, broom really loud.

Vaughn almost saves the film with his trademark brand of inappropriately behaving, lovably loutish, big lug, especially in a very funny, climactic intervention scene.

But the film veers lamely fROM plugs for the Chicago Black hawks, Budweiser and automakers to details about Nick’s personal failures, including a fondness for “happy endings” delivered by a 19-year-old Vietnamese massage therapist.

Connolly, who won an Academy Award for Howard’s 2001 drama “A Beautiful Mind,” is required to be sweet and beautiful.

No sweat. Ryder, also a shrewish Priam ballerina in “Black Swan,” relishes the evil adulteress role here, and in one confrontation gives Vaughn a run for his money. But half the time, you wonder why James, who starred in his own TV series and carries his own movies, is playing second banana.

If you must see “The Dilemma,” see it on a plane.