It has a pressurized cabin, enabeling it to operate at 41,000 feet. It is the fastest turboprop in the world, with a speed of 395 knots (about 730 km/h). In addition to the unusual engine arrangement, it has the main wings at the aft of the aircraft, and "canard" wings on the nose.
Check out this video, where you get the P180s cocpit explained!
About the design (from Wikipedia): The Avanti's turboprop engines are placed on a mid-fuselage, high aspect ratio wing, located behind the cabin. The design utilizes both a T-tail and a pair of small, fixed anhedral forward wings that lack control surfaces.
The arrangement of the wing surfaces allows all three to provide lift, as opposed to a conventional configuration, where the horizontal stabilizer creates a downward force to counteract the nose-down moment generated by the center of gravity being forward of the center of lift. This is patented as "Three-Lifting-Surface Configuration" (3LSC).
The Avanti II's forward wing has flaps that move in concert with main wing flaps. The forward wing pitch angle is set so it stalls before the main wing, producing an automatic nose-down effect; its five degree negative dihedral keeps the stream wash interference clear of the engine inlets, the main wing and the horizontal stabilizer