Its for a slightly bumpy track so a little extra ride height,
The only things I have been changing for a medium grippy/smoother track is usually the diff oil and lower ride height.

I don't run a shim under the front outer ball joint but I do run the slightly longer Associated ballstud part 31284, just for a little extra durability.

I don't have any old school HPI silvers so I usually stick with pink/pink as for me they work.