I remember reading good reviews on them and a couple of TT.net members actually set up a group buy for them. They are great low cost replacement. Next up is Z1 with OE fit at about 700$ but a bit larger volume (muck more thicker, very slightly taller and wider).
Godspeed, Z1 and GReddy are the only I know of that mount up to stock IC ducts with about full face coverage.