How much better will my instrument be if I use the top grade of instrument wood instead of the cheap stuff?
If by better you mean better sounding, you may be surprised to find out that there is no evidence that higher priced wood has any advantage over less expensive wood. In fact there is much evidence to the contrary. Anyone who has seen a number of violins built by the Cremonese masters can attest to the fact that a lot of what are universally considered to be the best sounding instruments are made of wood which would be considered of low or even questionable quality today. There is a Andrea Guarneri violin with a big (huge!) knot in the top, right under the bridge. In some master violins with two piece tops, not only aren’t the pieces book matched, they don’t even come from the same tree.