In response to the Q regarding the P3 having a 'pipe' laying on top of the wing inboard of the #2 engine, I know of no such pipe.
The only component that 'dirties' the upper wing surface of the wing, as far as I recall, is the fuel jettison pipe. This pipe outlet is only about 2 foot (60 cm) long, and located right back almost at the wing trailing edge, on the left wing, right inboard near the aft wing fillet. It does not run anywhere near the engine nacelle! It's located there because fuel can only be jettisoned from the centre tanks.
It's so close to the fuselage that it can only be seen from the port overwing hatch window, or the port aft observers window.