Plan lacked good faith that did not “purge the taint” of purchase of luxury car five days before petition. On August 5, 2011, the debtors traded a 2007 Lexus RX 400H and a 2007 Lexus ES 350 toward the purchase of a new 2011 Lexus RX 350 for a total purchase price of $46,900. The Chapter 13 petition was filed on August 11, 2011. “They chose to trade their two cars for a new one. In the process, they sought to obtain a benefit—a new car—at the expense of their creditors. . . . But for the trustee’s keen attention to detail, they would have been injured by the debtors’ conduct.”