Heh, the future of performance cars (in my opinion) is not about achieving horsepower milestones, it's about merging the right technology and materials together to produce the best possible combination of performance/utility. Clearly, the goal of the SRT team is not to produce a world class drag racer, but a car that can stake its reputation on track performance. Horsepower is the first thing that everybody notices, but it's really the cheapest thing to increase to make up for the other flaws of the vehicle. Look at what the viper ACR did at Nuburgring with a worse power to weight ratio than its close competitors and also don't forget how good the Nissan GTR is on the track, despite its lack of power and heavier weight.
At some point, pushing more and more HP has to stop--it becomes more dangerous for regular drivers to handle that kind of power and (as others in this forum have suggested) diminishing returns starts to take its toll. It seems a bit ridiculous to me for non super exotics/hypercars to venture into the 700-800hp realm as a stock tune. It's fascinating that actual race cars of around 500hp or less can totally demolish road cars with astronomical horsepower ratings. I wouldn't ever expect a road car to compete with an all out race car, but can't we move toward the direction of race cars by reducing weight and maximizing handling and technology rather than escalating the horsepower wars? Let's be honest, if all we're looking at is the horsepower rating, isn't that a bit one dimensional?