here is the best way to explain them
the 12 ports have very broad power.
the cubs are more blah and a bomb on the power band.
the main difference i felt was the 12 port would pull more off idle to the pipe.
while the cubs dont really pull as well to the pipe but when they hit you better be ready.
it totally depends on your riding style.
trails, dunes, and dicking off i would say go with the stockers
for dunes, dragging, and basically topend stuff, go with the cubs.
i will agree with loco the cubs arent trail friendly. they could be but just dont work as well.
hope that clears some stuff up. i will say both work well, its just as to what you want to do. if you want to play around and drag and what not, stockers.
jim should discuss stuff with you if you call him about what you are looking to do.