Gulfstream Aerospace Gulfstream IV (D-AFLY)

Nice photo - terrible paint job!

G450

Specifically, it's a GIV-X or a G450. It differs externally from the GIV by the thrust reverser design, the shape of the APU facing (under the right engine), the lack of windscreen wipers, and the presence of an EVS window below the point of the radome.