Corvette Z06 does Ring in 7:22.xx (starts at $74k)
Pretty impressive for the money. Looks like the model that did this time included the $10k package with the Ferrari Enzo's ceramic brakes and F599's magnetic suspension ($85k total):
http://www.autoblog.com/2011/06/23/2012-chevrolet-corvette-z06-laps-the-ring-in-7-22-68-shaves-20/
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73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs). Former: 73 911S, Two 951S's, 996 C2, 993 C2, 98 Ferrari 550 Maranello