My 2010 GT is lowered 1.25" on the rear and 1" on the front with Roush springs and shocks. With the rear lowered 1.25", I got wheel hop real bad, since the oem LCA's are no longer parallel to the ground, but higher at axle end....by 1.25". That was a disaster, esp in the wet. Put your foot into it, and you are taking weight off the rear axle. Lost it twice in the wet, just going to the dentist office and back..... and not on any hwy.
So in went the BMR LCA's, adjustable UCA, and BMR LCA relocate brackets. Used the top holes in the relocate brackets... and then the new LCA's were .75" lower at axle end..and I got my traction back. A year later, I dropped down to the middle holes...and now LCA's are 1.75" lower at axle end....and even more traction. The BMR LCA relocate brackets allow for a 2-3-4" drop. 2" - 3" is ample. 4" is too much. Get the LCA's too low at axle end....and the opposite of wheel hop is called...brake hop.
The issue was not the 555's, it's the suspension geometry with lowered rear ends. Before the suspension mods, I had the same traction problems, esp in the wet, with any brand of tire.