I would like to see some more limitations on the setup, but only on stuff that's physically impossible. "Strange" spring and damper ratio's might be silly, but not physically impossible to do. Same goes for tire pressures, silly but not impossible.
As an addition, i would like to see an option on the server to limit the setup options. Something like this:
[ ] Allow ride height adjustments
[ ] Allow spring / damper adjustments
[ ] Allow camber / caster / toe adjustments
[ ] Allow Gearbox adjustments
That way a server can run a "fully stock" race (basically like a cup race), or select some options to allow more freedom of adjustment.