Did you mean H-sports sway bar? A sway bar does not affect ride height (springs do).

Yes, FSD shocks with stock springs will give a more comfortable ride with better handling. Actually Koni recommends using FSDs with stock springs (not lowered springs).

 

How about stock sport springs? Will Koni with FSD perform better handling than stock sport suspension?

 

Presuming you are referring to the Sport Suspension + (SS+) that the S was equipped with, the FSDs will improve the handling as well as the ride harshness of the stock SS+. The FSDs have two tunings - 1.) for road bumps and 2.) one for body roll such as would be experienced in a turn. The FSD's softer road bump setting reduces (almost eliminates) the ride harshness from the stock shocks driving over the road. The FSD's additional tuning for body roll is actually better than the stock shock's spec. I haven't looked back on my decision to dump the stock shocks for a set of FSDs.