Christian,
it's a little trickier than that. The Illusion was designed around a canted side exhaust engine which put the header on one side of the fuse bottom but within the fuse. The pipe then coupled to the header at around the wing LE again within the fuse to pan transition. Because the header was on the side, the pipe ended up at an angle when coupled so a "bent" pipe was used to align the rear half of the pipe under the wing center in the tunnel.
The simpler alternative is to use a smooth pan and install the engine at 90 degrees as in the Tipo and use a pipe that runs "beside" the pan under the wing. This also gives you a full clear nose area for the nose gear. Tipo's and Illusions look mighty weird on conventional gear (tail dragger).
David