SimRacing does a commendable job of that. The high granularity of the difficulty settings allows for a number of different strategies when it comes to progressing from winning in the easiest mode to being a contender in the most accurate mode. For example, using the 'Rookie' difficulty setting, my 11 year old daughter won the pole and the race at Lowe's Speedway in Charlotte, NC. within 20 minutes of sitting behind the wheel for the first time. The second place car finished 10 seconds behind. She will quickly tire of such easy wins, and will want to increase the challenge without making it too difficult for her to remain competitive. She could do this through any combination of increased opponent strength, opponent aggression, or changes in the number of 'cheats' used. In my daughter's case, she won because the opponents were too slow. She struggled with the car, spinning it at least three times, so removing anything like car stability, steering help, braking help, antilock brakes, or traction control would make it more challenging, but in a more frustrating way. Instead, she can increase the opponents' performance by raising a percentage slider.
I chose a different path. I race with no driving aids turned on, and use the default 'race' and 'qual' setups for each track. I set opponent strength at 95% and aggression at 100%. At these settings I can usually qualify in the top 10. I seldom finish a race, though, since I almost always crash, but I enjoy the feeling of the more accurate driving experience. It's a far more challenging kind of driving, though. Without traction control, 750+ horsepower wants to spin the back tires. Without antilock brakes, it's easy to lock the rear brakes. Either of these will cause you to spin out. By the time you turn off all of the aids, most people sitting down at the wheel would not even be able to get the car out of the pits, much less get through their first lap without spinning and/or hitting the wall. That level of accuracy can be fun, but it's not for everyone. The ability to choose tougher opponents and/or more difficult driving rules in just about any combination ensures that everyone will eventually be able to tailor the settings to what best fits their style of play.
SimRacing also recognizes that PC audiences do not want to screw around with 'unlocking' various aspects of the game as their console-based brethren so often are forced to do. They do not want to have to place third or better at Daytona before they can race at Indianapolis. They want to race in the car they choose, at the track they choose, when they choose, without having to fulfill some arbitrary goal. SimRacing caters to that kind of instant gratification with a 'Race Now' mode, but also provides a more structured, realistic experience in the 'Career' mode. As a career driver, or owner/driver if you're a control freak, you can choose to follow the 2005 schedule of one of NASCAR's three premier series: the Craftsman Truck Series, Busch Series, and Nextel Cup Series.
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