Does input impedance change the tone?

Although the Axe-FX 3, FM9 and FM3 are all mostly the same on the inside (minus cpu power), the Axe-FX boasts a variable input impedance that actually changes the analog circuitry on input one. Does this have a great effect when it comes to vintage effects like fuzz? Does this render all fuzz tones on the FM3 and FM9 completely useless? Let's find out...