Here's my two cents concerning the debate.
Limiting setup options can be or can not be a good idea. It all depends on the reasons invoked :
- Reason 1) In real life you don't have such precision adjustability for aftermarket parts on road cars. Valid point, makes sense <--
[GOOD REASON].
- Reason 2) People make setups that doesn't make any sense for me, and any attempt of making my own setup result in a fail, so let's limit those options because I want to be as competitive as them. Jealousy, lack of dedication. <--
[BAD REASON]
Apart from racing, one of the thing I really enjoy with LFS is messing with setups and increasing my knowledge about car dynamics. When I work on a setup, it can take me up to monthes to find the perfect settings
for me. When I look at some SetupGrid or Inferno setups, I sometimes don't see the point of some of their specific settings. For instance, in a RWD car, Toe In at the front is something I find quite stupid, and when I switched to toe out at the front, my laps improved by around 0.7% of the WR time. (so a range from 0.4 to 1.2 seconds depending on the length of the track). But I'm sure it makes sense for their view of setuping, and that they are more comfortable with it, and that is what matters.
Let's take the example of FWD cars. People say "God, I can't understand why a XFG doesn't suffer from massive understeer at the exits, as it should do...". This is the trick of setuping, because people want to make the cars more balanced overally. Let's take a look at the toe at rear wheels on a FWD race cars IRL. You'll notice they have slight toe out at the rear, in order to prevent that understeer to happen, especially in exits. But is it unrealistic ? Is it unrealistic to dedicate your time when making setups to prevent a FWD car from understeering really bad at the exit? No, it's the job of what a proper setup can do.
What would be unrealistic is if your XFG could spin the real wheels like the XRT, with a tuned setups, which is not the case...
Chopping seconds and positions off your records is something very gratifying in LFS, but there is also a "quest" about making your own setup as fast as it could be, which is also very gratifying as well
A final thing about setups ? The best way to make a setup isn't to follow advices of LFS Manual. LFS Manual is a very good beginner's guide to understanding how a car can behave, but you can only fully grasp the importance of each increment you change while testing them, in respect with what you have learnt about setuping, should it be on LFS manual, race books, etc.