What have you done to the front and rear suspension (IRS) to improve performance/ reduce binding etc that doesn't make the ride noticeably harsher? Spherical bearings??

I see FFR offers a bump steer kit. Anyone have any experience with this?

Also, I understand the IRS hub is attached partly solid to the frame and partly with bushings, which doesn't make sense to me. Any downsides to replacing the rubber bushings with solid aluminium bushings?