Into the intake... you can get something like a 50/50 that will send half to the intake and half to the atmosphere, but that's a different product. No compressor surge, it just makes less air get sucked through the air box.
If you moved the MAF sensor, then it would no longer see a consistent pressure. It would be a far more complex sensor... right now it just measure velocity, and
massflow = area * density * velocity
But if you make density no longer a constant (as in, changing the pressure)... then it no longer has much use. You could somehow integrate it with the MAP I suppose, but... meh... really, this system works fabulously for anything but people who want aftermarket BOVs....