My colleage has just added the aluminum kit to his black Cayman. I think the aluminum is highlighted most in yellow & red. In the black, it seems just right. Just like the standard front aluminum spoiler. I can try & take some pics if you like.
Yea, leave it black. I got the Cayman front bumper on my Boxster and I even painted the lower lips black. With the silver lips the car doesn't look low enough IMO.
I think the hi-res shots taken in the studio can be really deceptive. How your car will actually look in the real world may be a let down. With enough clever lighting, clever camera angles, Porsche can make anything look so good, we all start drooling over it.
I think your car will look absolutely gorgeous just as it is but it's your choice...do what your heart tells you!