My Legacy has been running smooth with the standard Hartzel 72in 3 Blade. I did notice the engine mount to firewall bolts turned about 1/8 to  1/4 turn when re-torqued at annual. FWIW, A vibration in panel or glare shield might be from the firewall; however,  the control stick would alarm me as this is usually an indication of flutter.  The Legacy elevators have a concave shape, I’ve seen some  builders smooth/fill this out. This is wrong as the concave shape is by design to reduce the chance of flutter.