As a kid, Daniel Ha was into two things: cars and computers. Growing up in Milpitas, California, 50 miles from San Francisco--where, in 2007, he would co-found and run the website-commenting platform Disqus--he tinkered both with Web programs and with a manual-transmission Acura Integra, which he bought at age 16 without a clue how to drive it.

"I convinced my dad that my friends had taught me how to drive a stick," says Ha, now 29. "Every day after class, I'd practice driving around the block. Within a week, I was good to go."

Today, Ha relaxes by working on cars--and racing them. Every other month, he books a few hours at a track and tries to better his personal records. On other occasions, Ha rents luxury rides and cruises local freeways. Highway 1 north of San Francisco is a favorite, as is Skyline Boulevard, which cuts through the Santa Cruz Mountains and offers postcard views of the San Francisco Bay and the Pacific Ocean.

He's gotten to know many cars this way, but Ha's vehicle of choice is a BMW M3 that he bought while a student at the University of California, Davis. He intended then to strip it and make it track-ready. Instead, the growth of Disqus, having led him to leave college as a junior, forced him to shelve that project, too. But about a year ago, Ha began work on the M3 again, and he hopes to get it on the track in 2015. "My goal is to make it very uncomfortable to take on the road," he says. "To make it pure track equipment. Just a toy for the track."