since you didn't mention the miles on the car and since it is a 98 you are better off also replacing the struts, go with the BAT or Koni Kit and call it a day ...
No, the springs are what lower the car. If you want to do it right replace the struts with some performance ones like Konis or the Bat kit and then put some lowering springs on it. I've got the koni struts with b&G springs, lowered the car about 1.5" and it rides beautifully.
if you don't replace the struts plan on bouncing ALL OVER the place in about 2 years. Thats how long mine lasted before they blew completely. Its also a lot easier to do the work while you have them off the first time anyway - what's the point of putting the original struts back on just to have to take them off again in a very short period of time to replace them. I guess I learned the hard way on that one :blackeye: