Old post on the taxonomy of wusthof knives:

http://tinyurl.com/3p59y

The Grand Prix have better blades, being forged, than the Gourmet are.
Essentially, the Grand Prix is the Classic with a different handle.

The Grand Prix use the less-expensive plastic molded handles, which
some people think are more comfortable than the squared handles of
the Classic, though some people think the squared handles are more
maneuverable.

The Gourmet models use a much cheaper, stamped blade,
and they lack the bolster (the metal finger-guard between
the handle and blade), so they are overall much cheaper
and lighter.

The Gourmet do have rivets in the handle, which you may
prefer the look of. And it is the squared-off shape
of the Classic handle.

The discount on the Grand Prix set you're looking at is
a very good deal, but, as you noted, you're only getting
three knives, where the Gourmet set adds a utility knife
and a set of shears.

So it's a question of quality vs. functionality, and as the
prices are identical, it's up to you.

--Blair
"Do supply and demand proud."