To lower it with the stock suspension you would have to cut your springs. However this would really screw up the car. The springs would not be stiff enough and the shocks would not move through their normal motion. DON"T DO IT.
For $250 you can get some H&R springs if you are really interested in lowering it, but I wouldn't change springs without changing shocks and struts. The total for parts for the whole package should be about $750 and not but 2-3 hours of labor