The simple answer is everything matters! Violins are typically spruce tops, maple back/ribs/neck. Every piece of every type of wood has its own density and flexibility and sound. Cut matters, particularly with spruce, particularly in violin family instruments. But it all works together to form a unique voice. Same goes for guitars of all types, and in combination with different pickups. It’s good to think in generalities about how different wood types may influence sound. This inevitably leads to wood choices that are tried-and-true - there’s usually a reason for traditional choices. Add to the mix the player’s perception and preference, and it all gets mixed up! I don’t enjoy complicated debates about whether particular woods/components are better or worse, they’re just different to different people! One reason I enjoy also making basses and violas is, their players tend to be more open-minded about use of less conventional materials/design choices than violinists! The guitar world is wide open in this regard, very refreshing to me. But I still respect the standard woods of the violin family, because wisdom of centuries reconfirms over and again the success of traditional choices. Long answer...