Exact same fit, foil is part of the x-wave series, so just the 85 flex and the shock absorbers. But yes, if you fit an x-wave 10, you will fit a foil boot.
what Nomensteven said, the shells are from the same mold. for salomon you have the Performa mold, the x-wave mold the falcon mold and then the spk mold. there may be some others though.