coil overs are a more expensive set up although they are adjustable so you can actually lower and or raise your car whenever you choose to...shocks and springs are an easier and cheaper (not cheap in quality, just cost) set up..all you need to do is rent a spring compressor from advanced auto parts ($40) and they refund your money once you return it..compress the spring to fit over the shock/strut and replace the cap...you can probably keep your old sturts/shocks depending on how worn they are and depending on how low you are gonna lower your car

so basically go price a set up springs and shocks...