In this set Quickboost offers a drop-in replacement set of exhaust pipes for the Trumpeter C-47. This set eliminates pesky mold seams and provides a deeper more realistic exhaust opening. The exhaust pipes in the kit and the QB replacements appear to have built-in mufflers. My guess is that Trumpeter depicted a later style exhaust. The Monogram kit, on the other hand, has a short pipe with a more turned out opening. This earlier style is more appropriate for the WWII aircraft. Working on the hunch that the QB pipes are a later style, I went through my reference and I have found pictures of Vietnam era Gooney Birds with such a pipe, including the AC-47 gunships. This also includes the C-47s the Army used for VIP transport in CONUS. So if you are modeling the later aircraft, including the Monogram AC-47 release, these mufflers would be more appropriate for your model. Highly recommended.