Hay. I know the SES models have a new 22mm front sway and the same old 20mm rear sway bar. I think the "s" and "SE" use the 18mm front but I'm unsure if they use a rear. I was thinking the same thing as well. I know the 22mm progress rear bar made anoticable differance in my 07 ST, I assume a 21mm rear bar would make some differance.