At 100% crime fighting, you get the last health upgrade. Everyone seems to be getting swing speed 7 differently, but here's how I got it:
1) Did 3 races, got swing speed 6.
2) Did 3 more races, got wall jump.
3) Did a crapload of races, got quadruple air tricks.
4) Kept doing races, but I didn't get anything else so I stopped.
5) Did the last MJ mission, and I got swing speed 7.
Now, some people have gotten swing speed 7 doing races, and some people got it just for swinging around. Best educated guess is you have to do a lot of swinging to get the last swing speed upgrade, and the races are just a means to that end.
I also completed the endurance trials and the time trials, but I didn't get squat from that. Not even a "Good job!". *******s.