Imho (and usually my opinion brings controversy) read a bit more this thread what is the purpose of the suspension on your car, what coilovers mean in order to understand a bit more what you are doing/where you want to go with your car.
Then come back and ask anything you want to ask.
A few pointers, if the dampers in your suspension are gone then you really got to decide what you need depending what you want from your car. but if your suspension still works do take the time to read the whole thing. Its not just a couple of minutes read