I am going to get the Eibach Pro System Plus and was wondering if there was anything, other than an alignment, that I'd need for my 2011 GT? Would I really need to get caster camber plates or are they just nice to have?

 

I would replace your upper strut mounts.

 

I didn't need caster camber plates, but I had the steeda upper strut mounts which adjust camber slightly.