I just got my roof wrapped in gloss black and my car is Space Grey.
Honestly you could barely tell when you are looking at the car from the ground. It would be even less noticeable for your color since it is already so dark. The only time it looks good is when you are looking down at your car from a elevated place which isn't very often. On the road nobody is going to even tell the roof is wrapped.
Not worth the trouble if you ask me.