This was the toughest stage of the game so far and took me a while. After fully maxing out several vehicles and trying many different strats, I went with maxing out the V8 Muscle Car for its speed and tight handling and just doing laps around the boss arena chaining sheild power ups. I tried to keep the sheilds active by grabbing them as soon as they spawned. The boss will eventually kill itself by running into fire hydrants. Pretty shitty section. Very unclear what to do. I read about using this car and some of the strats online, when I was trying to figure out how to fight the boss. You do almost no damage trying to attack it with your weapons. It was still very close, but the method I used here wasnt too hard to pull off.