I tried that setup using Eibach springs because it was floaty with both Eibach and Str.Ts in front.
I really liked that setup at first. The ride was smoother and even seemed sportier too than stock. However after getting passed the initial satisfaction of the improved ride and handling (it also looked great too!), I noticed a squirrely feeling on any freeways with moderate to heavy bumps at high speeds. I originally thought it was worth it but after awhile it began to wear on me because in my area there simply aren't any smooth highways and I probably travel 85%+ on highways.
After a little research I realized that the Str.Ts were really intended for stock springs and not aftermarket so I gave that a try instead. While it didn't initially feel as nice as mixing the dampers and it loses that nice drop, it also didn't have the squirrely affect and it still improved the ride over stock. Some performance is lost with this setup vs stock but it's not significant...unless you are the racing type. In that case I'd recommend the yellows instead.
I miss the performance boost and drop of mixing the two but this setup feels more refined which is somewhat important to me also and I can't help wondering if the squirrely effect would cause other problems further down the road. I do plan to use a taller tire when these wear down to at least retain the dropped look though (if I don't drop my car again first and put the Bilsteins on it next time around...)
That said, I think part of the problem was because the Str.Ts combined with the softer Eibach springs make a bad combination as they are both too soft to be used together. You may have better results with these other springs because they are stiffer which may be a closer match to the stock springs but maybe someone else can chime in that knows more about that than me...
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