ok, explain this to me

When you lower a car, you increase the spring rate.. this provides less travel up and down, both in motion and when you load the car (passengers and gear). Is that a correct analogy?

Approx how much should an m3 be sinking(not the best word) when you put 2 200 lb people in it 1/2". 1", 1.5"?

I can't sit in teh car and measure right now, but i will, but what is the realm of realistic sink and when lowering an inch or so, how do you calculate the spring rate so you don't sink as much as stock. I.e. is there an equation like

stock ride height / initial travel = spring rate + coil height

somethign to that effect?

Thanks, your help is much appreciated.