spending the money to get a coilover system (500+ dollars generally speaking), rather than just a coilover sleeve, will result in better adjustability and better handling than a set of shocks and springs. if you get the sleeves on stock shocks (90 dollar coiloviers through 400ish coilovers), you will blow those shocks with a quickness and find yourself bouncing around quite a bit. i agree, with tsispyder.. budget = springs and a set of decent shocks combined with a camber kit (depending on the car you drive) should do you over just fine. if you have 1000 to 2500 dollars to spend, i'd strongly recommend coilovers.