After exiting door 1 in the Agency, continue on the street until you reach an intersection. There is a ramp truck on your left, down the street. Take the truck to the intersection you were just at and proceed going down the street, past that intersection. You should see a ramp going to the highway. Place the truck at the top of the turn, then go down the street with the Agency SUV and launch off the ramp. You can easily get a double frontflip. This also helps with getting driving experience.
First, defeat Cowell in the Central Point building on Shai-Gen. Note: Make sure you have leveled up your driving skills to do flips in your SUV. Drive in the building, get on the elevator to whatever floor it is, and drive up the ramps until you get to the opening where you see Wang's building across from you. You do not have to drive very fast but must have just enough speed to clear the railing, while getting the most out of B. It is possible to do three flips this way.