there is not a lot of difference in lowering springs, other than the amount of drop . . . I don't think there are really any "bad" lowering springs, except maybe some super-cheap made-in-china ones that you might find on e-bay
I would recommend you look for the amount of drop that you want and don't worry too much about brand
the spring rate is a secondary consideration; if you don't want to change out your struts and shocks, you can look for springs with about the same spring rate as stock
I would recommend you look for the amount of drop that you want and don't worry too much about brand
the spring rate is a secondary consideration; if you don't want to change out your struts and shocks, you can look for springs with about the same spring rate as stock