I have collected and built a few Hasegawa P-51B/C's over the years. The Hasegawa exhausts are adequate but do not have the flanges and are not hollowed out on their ends. I like my exhausts drilled and find this task very tedious. Quickboost solves this issue. This set is cast in light grey resin with no molding flaws, and is designed as direct replacements for the kit exhausts with no modifications needed.
The Quickboost exhaust fit perfectly to into the Hasegawa cowl (see photo). I also test fitted these exhausts into the Academy and Revell Mustangs, but they were not very good fits for either so they cannot be substituted for the kit parts. Perhaps in time the good folks at Quickboost will make exhausts to fit these kits as well. The MRSP is very reasonable and really will dress-up this area. I recommend this latest Quickboost update for the Hasegawa P-51B/C family of kits without reservation.