SSD in standard form is a little closer to the SE than the SX. But we do have more suspension on the SSD than the SE and larger coils (standard SSD uses the same suspension as the SX). We can tailor things to a specific application to a certain extent as well... if we know when the order is placed. SSD with flatwinds is much closer to the SX. I feel that the Q is on top of both of those in just about all applications (from both my and customers experiences).