I have an "L" shaped ranch -- the long part ot the L is the house and
the short part is the garage. The entire inside of the L is filled
with driveway. There is one downspout at each end of the L and the
space between runs about 80 feet. In spite of 6 inch gutters, the
downspouts cannot handle heavy rain and the water comes gushing over
the top of the gutters near the downspouts in heavy rain.

Is it possible to put two downspouts next to each other? Is there any
kind of "supersized" downspout I could use instead?

Thanks for your thoughts.