Hollywood Hot Rods and Pure Vision are given four days to turn a soccer mom minivan into a super car before their creations are put through the paces at Willow Springs Raceway. The winner will progress to the Los Angeles finals.

Speed Unlimited and ES Motorsports go head-to-head to transform their hearses into hill climbers. The garages have four days to go from sedate delivery vehicle to hill-conquering beast, then face off on a 33-foot hill and a 45-degree incline!

The Soccer Mom Super Car and Hill-Climbing Hearse winning teams battle it out to reach the national final and a shot at $100,000. Which team can turn their Firebird into a flying car and cover the greatest distance after taking off from a 200-foot cliff at Eagle Mountain?

In Detroit, Team Z Motorsports and Alternative Automotive Technologies must take the front halves of two front-wheel-drive cars ... and make them into one car.

Monkeywrench Racing and Voodoo Choppers are tasked with taking two motorcycles and making a single four-wheeled vehicle with one purpose in mind: to pull the longest wheelie they can down the mile runway at historic Grosse Ile Municipal Airport.

The winning teams of the Push Me, Pull You and Four-Wheel Wheelie Machine challenges tackle the tricky realm of treaded vehicles, as they attempt to turn trucks into tanks capable of taking on the obstacle course at the Eaton Proving Grounds.

In Atlanta, Lou and ACP each wheel an electric golf cart into Atlanta Air Exchange and Mild 2 Wild. Both shops are run by fathers, with sons working for them. Which family can focus on building an effective underwater vehicle?

Everyone fantasizes about having a car with James Bond-like accessories, such as rockets, spikes and smoke. Batlground Motorsports and Auto Extremes come face-to-face with turning that fantasy into reality.

Personal watercraft are great vehicles for the water. But can they be turned into hovercrafts that can work on both land and water? The winners of the Underwater Vehicle and Spy Car challenges duke it out for the last slot in the national final.

For the Ultimate Car Build-Off final episode, the three city winners have to make a car or truck drive on water. The winner will walk away with a grand prize of $100,000.