I recorded the show on my DVR just to see the Karma's TV debut
This was clearly a paid product placement. The car was in three scenes and got six or seven minutes of screen time (in a 24 minute show). There was also an exchange between the main characters about the car.
Ashton Kutcher plays a broken hearted billionaire who owns the car. He asks Jon Cryer's character to go out to take his mind off his heartbreak. This is the first time we see the Karma and, as in most of the scenes we see the car, it is an interior shot as if we were looking at the characters through the windshield.
JC: "Nice car. What is it?"
AK: "It's an electric Fisker. State of the art lithium ion technology supplemented with a turbocharged engine and solar panels on the roof"
JC: "How much does something like this cost?"
AK: "About 100 Grand. It's great for the environment. I don't know why anyone would drive anything else"
Then Jon Cryer makes a joke about crushing poverty as a possible stumbling block.
Later, Ashton gets worked up about his relationship troubles and starts accellerating. Jon gets more and more nervous and starts calling out the speed: 80mph, 95 mph and 103 mph are mentioned. Ashton whips around a corner at speed and Jon exclaims "This thing really takes the corners". This and later exterior scenes of the car weaving through traffic and barrelling down the street (in obviously accellerated footage) drives home the point that this is a high performance car.
All in all, not a bad plug. The only downsides are that they never mentioned the name "Karma" (this may be intentional, as the front and interior of the Surf is indistinguishable) and that all of the scenes involving the car are at night.
I've never watched the show, and I'm not sure after this one episiode I'm about to start, but Jon Cryer's character did have one line that made me laugh out loud. I'm paraphrasing, but he mentioned that when he was in high school his only girlfriend was a poster of Molly Ringwald.