I have the Steeda piece, although many will probably disagree, it is mostly unneeded unless you have a ridiculously high spring rates and need to tune out oversteer by installing a front swaybar. I have adjustable lower control arms and shocks/struts as well as Super Sport springs. I can deal with a small increase in oversteer by stiffening my rear shocks to make up for it and keep the struts in the middle of the road.
i plan on doing the mm rear one as well, and i do believe MM says the stocker is plenty stiff. mine would be adjustable for the oversteer anyway and i have fairly high spring rates as it is. my spring frequency is around 1.8hz.