If you have your car lowered significantly (more than 1") and/or you have front geometry correction, there is a good chance you may need bumpsteer correction. On the S550, lowering more than 1" is considered quite low and it's not like the S197 where 1-1.5" drop is basically necessary. The geometry of the car is pretty good. Don't overdo it. The lower you go, the stiffer you'll need to make the car due to the increased roll couple and reduced ground clearance. IMO the only reason to go to a 1.5" drop or thereabouts is if you plan to have significant front-end aero and need to get your splitter height down. At that point, the above about stiffness is especially true.That's interesting. So the takeaway from this on bumpsteer kits is....If running stock to 0 toe, then bumpsteer kit is pretty useless. However if some degree of static toe out is already employed, controlling the amount of toe out added in compression could be a good idea.
Is it more about compression during a corner or actually hitting a bump?
Seems to me that cornering aspect would be more useful, and just people think of actual bumps when hearing "bumpsteer". If I'm running toe out and turn right, weight is transferred to the left front, and compresses. Then if the toe out increases on that side as result of the compression the tire is turned less, and that's the tire with the most traction.
Also any insight into situations where the car is using different sized wheel and tire heights, wouldn't that change the geometry of the control arms?