Instructions
Complete the "Cesar Vialpando" mission. The mission starts with a clip, as usual. After viewing the opening scene, go to the Loco Low Co. garage in Willowfield. The garage is not yet fully unlocked, but one of the workers, who owes you a favor, will make minor modifications on your car so you can compete with Cesar Vialpando. After the modifications, go to Unity Station where a rival gang member will be waiting to challenge you.
Meet the Varrios Los Aztecas gang member, who will challenge you to a lowrider competition. Bounce on your car by using the hydraulics that were just installed. You will collect points and win the wager. Here you will nearly get into a fight with Cesar Vialpando; refrain from fighting. Afterwards, you will shake hands with Cesar and both of you will go your separate ways. This will complete the mission and open up two mod garages---Loco Low Co. and TransFender. The garages will show up as red wrenches on the map. Grab the red wrenches and you will find yourself inside the garages where you can modify your car.
Complete the mission "Zeroing In." The mission will start with you and fellow gang members adjusting a new electronic device that allows you to zero in on other vehicles by tapping into the occupants' cellphone signals. After you get into your car with the device, get close to the target vehicle by following the signals on the device.
Get within a few feet of the target vehicle and use the PITT maneuver. The maneuver involves a controlled hit to the rear of the target vehicle to force it into a spin. After the target vehicle spins and comes to a halt, get out of your vehicle and jump into the target vehicle and bring it to the shop. This completes the mission and opens up the Wheel Arch Angels mod garage. The garage will show up as a red wrench on the map. Grab the wrench to enter the garage and modify your vehicle.