Can I put coilover all around a 120y??If so how?

Fulcrum sell an adjustable spring platform kit that you could use to convert your front strut legs to a coilover set up. I think I paid about $70 for a pair.
Regards Matty

Strictly speaking, the fronts are coilovers anyway.
To lower the car, use lowered springs, to stiffen up the damping, use Koni shocks [if they are still available] or other shock insert. What else do you need to do to a front suspension?

About the rear now what can i do to the rear suspension to stiffin it?

hehe, B210 rear suspension is already too stiff ... Do you mean how to make it handle better? Lowering the rear is the normal way.

You can't just bolt on coilovers in the rear because the shock mounts aren't designed to hold the weight.

We'll soon find out. My b110 sedan has coilovers on the rear of it, mind you they are incorporated with a 2 leaf pack leaf spring.

Craig

Yeah, I can see that. On your B110 the rear coilovers aren't holding the entire weight of the car.

On a related note, I drove my old sedan with only two leaves for some time. The ride was better ... but the springs kept getting lower over time ...