Here is what i did to my car last year.
Image 1, I welded a crossmember between the shock towers, and used the rear bolt on brackets from GNS performance to tie together the rear of the frame.
Image 2 , HRpartsNstuff Upper and Lower control arm reinforcement brackets.
Image 3,4,5 show the installed Frame FX kit from Hellwig notice the difference in frame width between image 1 and image 3,4,5
with these installed i could lift the car in front of the rear tire and it will pivot on the opposite tire.