The red covered inlet is the fuel inlet from the tank. The DZ uses a fuel pump instead of a pressurized fuel system. You will vent the fuel tank to atmosphere just like a gasser.

Central Hobbies has a lot of different exhausts for YS engines, the YS 1.20-1.75 all use the same exhaust thread, but I will caution you that the standard 1.20 muffler will choke the DZ.

Do a search here on the DZ and you will learn a lot.