The winners will have money to set themselves up, or retire in style. They will have rep beyond words, and will be in the highest demand. The benefactors are indeed as well backed as they seem, and have the cash to make good on their offer. The characters will participate in a long series of competitions and runs, and conclude with the simple task of racing across the multi-national continent of North America. The benefactors are themselves backed by a corporation, Omnitek, and many of the runs they perform will be real runs, not set-ups, with the express purpose of catapulting Omnitech to the front of the line.
Every runner there is a target.
Everyone in the competition is sold out to someone from their past. The characters are going about their daily lives, and all receive email, phone calls, or hardcopy messages at about the same time of day. Each message is delivered in a way unique to the target character. One runner receives an email to a private drop-box, known only to a select few. So on and so on.