I ran this setup at Trackside, too, with JTG sauce the only, where the traction isn't as high as a Paragon track. Driver aside, the car was still very fast and easy to drive, almost lumbering.
Sometimes a car can be too stiff and can just be slower.
Unless your car is bouncing off the ground, that's really not true with a race car. I'd like to see an example of how and why you might say this.
From real race cars, springs absorb bumps in the track. The smoother the track, the stiffer springs you can run. The firmer the setup the less traction to the tires. I'll keep going firmer on this setup until the traction isn't drivable or the laptimes go down. If there are no bumps in the track to worry about, get the car as stiff as drivable. Too much traction when you don't need it just scrubs off speed and momentum.
Loose is fast. No matter what surface you are talking about; dirt, carpet, asphalt... its all the same.