Plot hole: When Dan asks Lucas how he managed to lie to Karen about his heart test results then successfully move out, Lucas tells Dan that he showed Karen Keith's test results letter instead. In a prior scene, Lucas hands Karen the results letter and she is elated to read no Hypertrophy issues. Being a very savvy business woman, Karen would have noticed the addressee on the letterhead was Keith, NOT Lucas.
Revealing mistake: When Dan and Lucas are racing Felix, from one scene to the next where the actors are replaced by stunt doubles. Close up, they are Paul Johansson and Chad Michael Murray, but from far away when the actual driving is happening, they are not the same people.