The game already has different range for different tiers. Why not just un-limit it? Regardless of what tier you're in, new season brings new setup range. It's just an idea to take the boringness out of seeing and using the same thing season after season.
If you were to use different drivers and suppliers season by season then would that not change how a car gets set up? Also, if the league host were to change the race schedule every season, would that not also change set up parameters for each track in terms of your car development?
So here is an idea. Have your league host change the race order every season. Also invoke a rule that your car must have different suppliers every season. Then you should have a more interesting time doing setups...
