I've never messed with shocks in cars. I honestly don't know what type of shock this is. I was assuming it's a coil over, meaning the spring fits around the outside of the shock.

I will note that most people tend to use too stiff of springs, or too much preload. They also use too mch dampening. It's one of those cases where less is more. Your goal is to keep the wheel in contact with the pavement not nessesarily prevent body roll. That's more the job of the chassis and anti-roll bars. It all must be balanced. Unless you have a stiff chassi like in a race car, it's not realiztice to have a ultra stiff suspension. It won't respond properly.