Bro,
besides just wanting to lower your car, bear in mind the other factors involved in this quest.
the task of lowering your car does in fact present quite a few options. I shall list them from cheapest & crappest to most expensive & best performing.
1) cut your existing spring. Make sure u cut off one exact coil or it will affect how your spring sits
2) replacement springs. These are similar to cutting your oem springs as they either have less coils (longer overall coil length, thus higher kg/mm) or a heavier gauge coil
*note 1 & 2 will offer sub standard ride and performance as the new spring rate is now unmatched with your struts, eventhough you have a lover centre of gravity.
3) New strut and springs or coilovers. These offer the best in suspension upgrades. Matched spring and strut rates.
Coilovers due to their construction offer a more rigid structure. Also they are height adjustable and depending on the models, offer rebound, compression and preload adjustments and on higher end models, hi speed and low speed adjustments on those items i mentioned and can rebuilable.