Idk if gktech has any issues with the z32 ebrake assembly but I hated the PBM one because installing the z32 e brake assembly is a pain. The nut that tightens that assembly interferes with the RLCA Nut so you have to cut the z32 e brake nut on one side so you can tighten it without it interfering with the other nut.
https://www.instagram.com/p/BQYYWdHjPR6/
Also my voodoo arms could barely fit the PBM knuckle, I had to bend the tabs a bit. I personally wouldnt recommend them. Only thing I am happy about is how my car sits in the rear now. Reading that blog from RelaxAmgio I would say Geomaster> Gktech > PBM. I dont drift my car or track it (yet), so I cant really give a input on that.