I do backside downhill in around 5:30 in a stock family sedan (4cyl Camry with cheap brakes and tires). Probably much faster in something that moves. I only timed myself on Ridge a few times, I think 9-10min in my first 240SX, but the engine gone done blowed up when I reached Horse Canyon Saddle. FYI, you need AAA's longer distance tow coverage to get off GMR cheaply, not their base coverage.