a 4mil long rod is the most common upgrade ppl do to a banshee...
with the minumal work for a 4mil your looking at about 7% gains... nothing amazing but if you hav the money and time you can easily get 80 hp out of your stock jugs with it... nice dune or drag port with some 35PWK, VF3, drag pipes, dyna, nology, timing plate, clutch, swinger, suspension, tire/wheels... you can get there...
but even if you dont go all out it will be a big improvment ovr stock for sure... what kind of riding you do? and list any mods and we can help you sort it out..