Will a guitar fx pedal make a lot of difference with the sound from my amp.?

[XXTheRealJesusXX]

Im using a fender mustang 2 amp and i want a strong blues sound but i cant get what im looking for when messing round with the amps settings so i was thinking of buying a boss BD-2 Blues driver effect pedal. Would that be a good idea or is there a better alternative im trying to get the old blues sound of people like muddy waters not the heavier more modern rock sound of newer blues influenced bands.