It depends what your goals are with your suspension. If you're wanting to just get a better stance with slightly better handling characteristics, springs will be fine. Although I will say that if you have the money for coilovers, I'd definitely do those. I personally love my current springs and don't mind the slightly stiffer ride but if you don't want to compromise any ride comfort, coilovers will allow you to get the stance you want while also allowing you to adjust the ride.
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