Once you are “in” the simulator, you land at the overview page. From here you can go into various settings menus to adjust the game and/or your car.
You will notice, if you look closely, that my Mustang has some pretty hideous colors. You do get some limited customization of the vehicle's appearance in iRacing. It's a little different than rFactor, though.
Through the web interface, you can customize some of the colors and choose from a selection of sponsor logos. My assumption is that these logos are there because the companies paid to be in the game. Anything you do through the web interface as far as customizing appearance is visible to all other drivers on track.
You also have the option to download a file to play with in a program like Photoshop or Gimp. From there you can use that, but it will only show your skin in your own replays. Other drivers will see whatever skin you had previously configured in the web interface.
I guess this is nice, because it keeps you from plastering wiener pics or boobs something that might offend someone with a thin skin all over your car. But I also want people racing against me to know that MotoIQ is kicking their butt!
As detailed earlier, certain cars/series do not permit you to adjust many things at all. In the case of the Ford Mustang FR500S, you only get some suspension settings to play with. On the 2011 Dallara Indycar, you get quite a lot of dials to pull, including aero, drivetrain, and other interesting settings.
As expected for a realistic racing simulator, tire change settings are adjustable while in-car and take effect on your next pit stop. Interestingly, there is also a tire temperature view. But it is not real-time. Much like most club racers, only after the tires come off the car (or the car comes into the pits) can the temps be analyzed. The temps are telling you about the last time you stopped in the pits.
One contrast to rFactor 2 here is the ability to have some hotkeys tied to various fuel and tire change settings, so that you can focus more on your driving and less on trying to hit that weird button on your steering wheel that you only use when trying to increase tire pressures…
If you bump into something on track that’s significant enough to warrant repair, if you need fuel, or if your windshield is too dirty (not really applicable in road racing sprints), you can change those settings while in-car, too.