Coilovers
the knob on the bottom will adjust the 'dampening' of the shock absorber (otherwise called shocks or dampers) Turning the knob one way will make the rise basically stiffer, and the other, softer. Max stiff isnt the best as although you wont suffer from body roll, your car will not allow for fast rebound, so your car will skip on the bumps and as the wheel wont be on the floor, err, it wont grip.
Too soft and the car will roll transfering the weight to the outside of the car and hence it'll understeer; whereby the car simpley doesnt turn enough and contines straight on.
Coilovers are height adjustable too by screwing the top the damper will increase the compression on the spring and decrease the distance lowering the car.
Cheap coils are normally only height adjustable, then others are height and damping adjustable.
My Si was/is on Spax dampers and springs and its pretty damn hard. It fun in the corners but pain in the arse over speed bumps and such like. I'd recommend the kit though as its good stuff. I'd buy it again, but I think I'd spend a little more next time and have coilovers.
Springs - £70
Springs and Dampers - GMax are £220 / Spax are £280
Coilovers - AVOs £550
Rough idea on the cost of things. Dont expect your wishbones to last more than 12months when you're dropped 60mm and your standard dampers would be shagged after about 12months on springs only too.
Hope that helps. Sorry if any of it belittled you, I dont know how much you know
