A lowrider (sometimes low rider) is an automobile or other vehicle modified so that its ground clearance is less than its design specification.
Yes, I can imagine that is the minimum requirement. However, it goes on to say:
Such modifications ...alter the vehicle's performance by changing the vehicle's aerodynamic properties, to lower its center of gravity, or to change the effective gear ratios of the drivetrain.This is where it gets interesting. You see the car in the background of the white one, to the right? That's not just jacked up to display its underparts.
video here. Not all of them do that - some are more about the custom paint, accessories and dashboard. So impressive.
This event was held as a fundraiser for the school whose playground it was in and there was a real community feel to it. San Francisco definitely has a much stronger neighbourhood/community feel to it than similar areas in London. But then people also manage to shoot each other more. Pros and cons I guess.