If your plan is to spend major bucks and re-do the suspension entirely, then the base is definitely the way to go. But if you're not going to modify it heavily, check out the SH. The difference isn't just in the ATTS, it's got a whole different suspension setup than the base (springs, shocks, camber, caster, arm mounting points, solid radius rods, bump steer, ackermann, etc. ) i.e. the suspension geometry is different.
As has been said, test drive both. See what differences
you notice.
Something else you might do if you can find a cool dealer (I did!) - pull the ATTS fuse from the SH and drive it around - as you start to push it, the differences between the SH and base suspension should be apparent.
That being said - the base Prelude suspension is still one of the best of any car in it's class - it's actually incredibly good. Have fun making your decision!
