+1 Not only will this protect the filament but it also serves to straighten the air before it hits the filament to allow for a better reading. If you've ever been inside a wind tunnel the same principle is used.I bought a set of hardpipes cut for relocation. I've run my MAF relocated to the pressure side for 2.5 years now with no problem whatsoever.
A word to the wise: DO NOT REMOVE THE PLASTIC MESH SCREEN INSIDE THE MAF HOUSING. Trust me on that.