In 2004, Keen competed in three races towards the end of the season, accomplishing two podium finishes in the Autometric Motorsports' SGS-class Porsche
Keen drove for Autometrics for the 2005 season also. He started strong with a 6th place finish at Rolex 24 at Daytona and ended the year in 5th place in Rolex points.
Keen drove the Shoes for Crews #80 Porsche 997 GT3 Cup car with David Murry for Synergy Racing in the 2006 season. With a podium finish in Mexico City and another at Infineon Raceway for the season, over all Leh finished 6th in points for the GT Class.
In 2007 Leh drive the Farnbacher-Loles #85 Porsche GT3 sponsored by Shoes for Crews and Recaro. During the 2007 Rolex 24 hours at Daytona, Keen, one of four drivers to drive the number 85 car, led the GT class for the first 22.5 hours. However, the failed to finish the race due to engine trouble. At the Second race of the year in Mexico City Leh finished second with co-driver Dominic Farnbacher.
He also competes in time attack racing. In 2007 Leh piloted GSC's Unlimited Class Mitsubishi Lancer Evolution and Modified class Toyota Supra in the Redline Time Attack Series and drove in Car & Driver One Lap of America competition driving GSC's Modified Class Toyota Supra.
Also known throughout parts of East Asia as something of a heart-throb, Keen is commonly spotted in various Asian magazines and advertising materials.