Either one its the same stuff really. You can lower it however you want to. There are springs you can get and just toss on in place of your stock springs. Then you have different strut/spring "kit's" like BAT and Koni. Then you have coilovers such as Ground Control(they require more work than your reg lowering spring swap does). Then you have a full coilover setup such as the d2's/ KSports. Correct is debateable. It is reccomended to replace your struts with some better valved ones for lowering springs, and you may as well replace the strut mounts while your in there since they are most likely worn as well. As far as what springs to buy, there are plenty to choose from. You have B&G, H&R, Eibach, Bat, Koni, and there may be more im sure. I have some new Eibachs here for my svt I need to install, and we are running Ground Control coilovers on my wifes cougar. The ride with springs will be better than the coilovers for sure but in the end its all in how low you want to go and what kinda ride your after.