I've got a jet dynamics #16 for my x4, may sound like a dumb question but when I fit it, the back where it fixes to the rideplate sits lower by 2mil or so, is that how it's meant to be?
If you ride in choppy water then a deep scoop grate will make you faster by keeping the pump hooked up. On flat water it might be holding you back a little.
I'd get a top GPS speed without it and then file a little if necessary. I would think the front blade will hold you back as easily as the rear one would. I'd measure how far each comes down from the hull.
I've got the same grate but haven't tried it yet. It looks like a giant scoop shovel so I imagine it's going to rob quite a few mph off the top end lol.