ya i have the receptor bug with crowbars, i wear them under the helmet and they fit well, obviously a bit of goggle sag but not too bad , wearing them over is alright too they lift a bit off my face on the sides but not enough to make it annoying. i like how they fit. and yes there is a plastic piece you can add to the back of the helmet so u can wear the goggles outside the helmet.
only complaint i have about the helmet is the earpieces dont sit flush with your ear and so it gets kind of cold.