The answer is that it depends. So not a great answer.
The amount of effort it takes to turn the wheel varies greatly among cars, depending on the steering gear ratio, the steering wheel diameter, the amount of grip in the tires, and the specific alignment settings in addition to the obvious question of how much, if any, power assist is in play.
The amount of feedback transmitted when you go over bumps or when the front wheels start to lose traction also varies by suspension design and alignment settings too.
There are far too many individual variables from one model of car to another for them to effectively implement a true simulation of the specific steering feel that each car produces. So we get a more generic model.
In reality, as an example, the 1971 Mustang would have had a typical-for-the-time vastly overboosted power steering setup, so the steering feedback is far too strong for that car in the game. Similarly, racing cars with slick tires have
very heavy steering and the amount of feedback from the wheel in the game is almost certainly too little for those cars.
Also, just FYI, most modern power steering setups are speed sensitive and the power assist is actually turned off completely by the time you're going 35 mph or so. This is because the faster the car is moving the less assist is needed and steering is heaviest at low speeds. Older systems (like the one in the 1971 Mustang) left the power assist on all the time, which resulted in very light, very vague steering on the highway.