I did it with my Insurgent (Took around 20 minutes of just looking through changed values)
http: / /puu .sh / hsh44 .jpg
http: / /puu .sh / hsh4C .jpg
(Yes, it was drivable)
Idk if the values are the same for every car, I'll test it now.
The Insurgent values are: (4 byte)
Competition Suspension: 1017370378
Sport Suspension: 1014350479
Street Suspension: 1008981770
Lowered Suspension: 1000593162
Stock Suspension: 0
(I tried to make my car float, but it would go up to -8,300,000 or so, then my car would just disappear into the sky (With me in it) and it would cause me to parachute when I jump out of the car.)
EDIT:
Yes, it does work with all cars.
http: / /puu.sh / hsifI .jpg
Just search for the last one, then buy the 2nd last suspension, then search for that value. (Or just search one value, then buy the other suspension, then search that value, it'll give you the exact number pretty sure)
EDIT2:
You have to go to LSC and get the value every single time you car blows up (Your new car gets a new Address I guess)
EDIT3:
It's different for some cars, I grabbed a Gauntlet, and the values were different.
Sport Suspension: 1004888130
Street Suspension: 1000593162
Lowered Suspension: 994352038
Stock Suspension: 0