Hi,
If it were me picking up a brand new black vehicle, I would polish it with SF4000 on white as a minimum to ensure that everything is removed from the surface. But then again, it also depends on what level of defects are in the paint. Please remember to mention to the dealer not to prep the paint and give it to you dirty. This way ensures you get the paint as unmolested as possible.
If they do prep the vehicle for you anyway, you may need to step up your aggressiveness to remove whatever the dealer hacks put in it.
But to answer your question, SF4000 on white assuming no one touches the paint but you. And to really bring out the gloss of the black paint they are so well known to produce, SF4500 on a black Hybrid pad before your LSP. This will undoubtedly give you that incredible finish you are after.
I would also apply two coats of WDGPS 3.0 with 24 hours cure time in between. Then top it with Fuzion to seal the deal and maintain with Wolfgang Deep Gloss Instant Detail Spritz and Deep Gloss spray Sealant respectively.
Happy polishing,
Mike