What? I put mine on B-Spec from the start... haven't lost a endurance race yet.
Just put it on level 5 "push" and turn "passing" on. Then, go to the race menu and turn up the speed to X3... and wait for the first pit. After that you can leave it on level 3 or 4 with "passing" left on.
Then it'll just go about it's business and win.
Also helps to slap on a stage 4 turbo and R1 race tires.
