I'd like to see a durability/etching/etc. comparison between the Synergy and FK1000P.
pgp- The GEP might indeed be to blame for the streaking as it's a "glaze-like" product that leaves stuff behind. Gotta be a little careful to not disturb that "stuff" when applying the AFPP...so letting the GEP set up and applying the AFPP gently might factor it. I'll admit I'm guessing as I just never had any problems with it. And lest it sound like I'm all anti-BF, I do like the way the GEP can work like a glaze underneath a sealant, good system IMO. I've even used them on stuff like lightly surface-rusted black-finished metal bits on the undercarriage and engine compartment, worked very well for me.