Whoah, what a thread to bring up, hilarious stuff.
Per title "best plumb back" Everyone has their preferences. Cheap, name brand aftermarket device that works, the Trust R is hard to beat.
They're like 230 clams, almost half that of a local made Turbosmart one. Compact and simple, does the same recric job a BOV is sposed to, but in a smaller form factor then stock. This is for a spritley BNR32 though where the twins, plus the y pipe take up a heap of room where a o.coiler should be