The Pagani Zonda is still one of the most eminently desirable supercars on the street today, making Ferraris, Lamborghinis and Porsches look downright plebian. But after eight years on the market, the Zonda is due for replacement, with test mules popping up here and there. Following the spy video we brought you earlier this month, this shot of a suspicious-looking Zonda test mule was caught undergoing testing. Although it wears the same bodywork as the outgoing model's, the suit fits a little looser after the Pagani's gotten back to the gym, and there's all sorts of vents and air ducts popping out all over the place. While Pagani seems hard at work in Modena preparing the successor to the current Zonda, AMG is reportedly working in Affalterbach on flipping the SLR's supercharged V8 around for the Pagani's mid-engine application.