Tarett sway bar links
 

Is there any advantage to attaching the sway bar to the spring plate rather than the factory attachment point on the trailing arm? It appears the tarett drop links are designed to go on the spring plates. I currently just have them attached to the trailing arm. Currently I only use the ecentric piece for a spacer.

Not sure if there's an advantage to using the spring plate as an attachment point, but being able to eliminate sway bar preload with the adjustable droplink is an advantage.

I'm not an authority, but I've heard others say that the geometry of the Tarrett solution is far superior to the stock set up... what that means day to day I'm not sure!

I have my Tarrets going to the spring plate. I have later Aluminum SC bananna arms on my racecar but still used the spring arms as the attachment point. I was told to do so.
I can tell you there was a very noticable difference when I switched to the Tarret bars from Weltmiester. I am sold on them. Make sure to adjust the preload with you (or you weight) in the driver seat. The bolts should just slide smoothly in without any force.