Not having a bright day, Mr. Brightside? Believe it or not, if you run the Slipstream Battle tests, you'll be able to have a sense of what this race is all about. While it is boring to race Renault Meganes (or are they Avantimes? I forget.) on the high-speed Le Mans course. Just be sure to draft them. In other words, when you get into a rival car's slipstream, you have the chance to inch closer and closer to a rival car at speed, and then overtake. Since you have only three cars to pass, take each one at a time. If you know how to tackle Le Mans' two chicanes and the slow corner after the Mulsanne Kink, you're in good company.
When you pull into someone's slipstream, try to overtake, hold your line afterwards, and then pull away from that car. If you sense the rival car following your slipstream, you'll need to get out of the draft by shifting to another lane. Keep doing this until you eventually reach the final car. Remember, don't introduce the rival cars to the front end of your car, or you'll get a 5-second penalty for your actions (meaning, start over!).
So Mr. Brightside, look on the bright side. This thing can be won. You just have to watch your speed, follow the racing line, and adjust to where you can overtake successfully.