Speaking about the amount of travel that is being used is quite difficult since many race cars use specific length rebound stops with or without in combination with preload that often can also exceed the preload needed to carry the static weight of the car (meaning that the car would in that case be at full rebound in the garage)
I would prefer to talk about wheel rates since there are a few rules of thumb that can be used:
Standard Road Car: 15 N/mm to 25 N/mm
Sporty Road Car ("ST- Versions"): 25 N/mm to 35 N/mm
Very Sporty Road Car ("RS-Versions"): 35 N/mm to 45 N/mm
Super Sports Car (Ferrari, Lambo etc): 50 N/mm - 70 N/mm
Rally Car in Tarmac Setup 70 N/mm - 90 N/mm
STW Touring Car Setups 90 N/mm - 140 N/mm
Formula Cars with high downforce ( F1, Indycar) 140 N/mm - 200 N/mm (and especially on the front higher than that)
Or if you like there can be given also an indication for the natural body ride frequency range:
Standard Road Car: < 1,3 Hz
Sporty Road Car ("ST- Versions"): 1,3 Hz - 1,5 Hz
Very Sporty Road Car ("RS-Versions"): 1,5 Hz - 1,8 Hz
Super Sports Car (Ferrari, Lambo etc): 1,7 Hz - 2.0 Hz
Rally Car in Tarmac Setup 2,2 Hz - 2,6 Hz
STW Touring Car / Tarmac Hill Climbers 3,0 Hz - 4.0 Hz
Formula Cars with high downforce ( F1, Indycar) 4,0Hz - 6,0 Hz
I hope this help getting some feeling for the numbers.
Cheers,
dynatune, http://www.dynatune-xl.com