I've used G, D & a GFB DV+ on my mapped ED30 and they've all worked fine for me, despite the common reports of the D type "leaking".
One thing I did notice with my DV+ was a bit of compressor surge, but after a strip down, clean up and re-oil of the piston, all is good again.
If you use a G, I think you might need a stronger spring if running high boost. I believe R Tech are looking into that.