It's in episode #70 (6x04), titled "Runnin' on E". I had heard a few months ago that the Roadster was going to make an appearance on the show based around a plot point that I guess didn't end up making it into this episode. However, if you're observant an orange Roadster is just visible for a second in the background of the last scene. A connection the Tesla already has with the show is that the character of the talent agent, Ari Gold, is based on Roadster owner Ari Emanuel. .