Correct.
Only way to use custom setups is to have it on simulation.
The game lacks customization options when it comes to the style of game you want to play. It's their way only.
Stability, auto braking, racing line, traction control. Basic settings in every racing game out there basically are missing in the 3rd entry of this series. Not a good look. Not sure why you can't use custom setups with stability on, but... not alot these guys do with the options for the racing model in this series make much sense.
Fun to play, no doubt there, but it leaves alot to be desired all over the place.