Seems to be a common theme. The Harrop Monster kit cleared up front and not the rear with my G6ET factory 19s. I went to great pains before getting the Harrops having being assured by Harrops themselves they will fit but still they didn't. Harrops experimented with new rear brackets but due to the FG rear suspension setup ,the large diameter rotors and the offset needed to clear componetry put the calipers too far out. Options were as you have already looked at 1 PBR rears from FPV/Territory Or 2 Get rims that clear big brakes, like I did. I was worried about brake bias and using an untested combo, so preferred to keep the Harrops fronts and rears together. Let us know how you get on.