As stated above somewhere by the chief groan recipient of the thread, it is all determined by pressure differential. That for some vehicle geometries and sub choices can be obtained using a bass reflex alignment that happens to have a "low" tuning frequency. For other cabin geometries and sub choices, it may require a variant of a transmission line etc. If it's engineered, high excursion may be a byproduct, but not a prerequisite.....nor are high subwoofer Xmax ratings always required. There are vehicles out there that raise scalp fur with nearly no piston excursion.