The OEM hood vents are already white (except the mesh portion which is matte black like all of the other mesh on the front, rear, and sides of the car). I don't think there is much reason to change the hood vents but I have seen some people do gloss black. If you do white front grills, you should do white side gills. In other words I think the front grill and the side grills should always match. You could do matte black, gloss black, or gloss white. Some people paint all of the mesh on the car gloss black. I think that looks good but it's a lot of effort for a small impact IMO. Good luck and enjoy the new car!
'08 E90 M3 - Alpine White - Sold
'13 E92 M3 - Silverstone II - Sold
'04 E46 M3 - Jet Black - BBS E88, KW Clubsports, Brembo BBK, SuperSprint Exhaust