Anything new will be better than your worn out stock suspension. The real decision you have to make is:
Door #1:M030 with slight lowering and slightly better sways but without ride height adjustability.
OR
Door #2: Cheap coilovers with ride height adjustability but stock sways.
Will it be Door #1 or Door #2? Both will be better than what you have now. Pick your poison.
When you have the money, this is the hot setup:
http://986forum.com/forums/general-discussions/35845-suspension-upgrade-week.html