Iv'e- BDT Motorsports have built quite a few ATC250R's and TRX250R's with aftermarket plastics, including Maier, some are full blown race Trikes/Quads for MX, FT, TT , WOODS customers...never installed the wire or brackets. I don't like the idea of drilling holes into new plastics, and you don't really need the wire or extra support it may provide IMO.
Carlos