Quin I run the Nismo rear spring , anti tramp rods and anti roll bar. Because I run treaded tires the panhard rod doesn't seem to be an issue. When I put super soft formula ford slicks on the car for Autocross (gymkhana) then it started to be an issue , as I don't run those anymore I haven't worried about it. I run some track days as well and with the current set-up I'm glued to the back bumpers of Lotus Elises in corners.
I have noticed a differance before and after the tramp rod on rippled pavement but not sure if it's enough write home about.

Tom