Andreas on Instagram: "Muffler comparison Magnaflow vs. Flowmaster Super 44. The Magnaflow muffler are much quieter in idle but produces a really deep and smooth sound when you rev it up. The Flowmaster sounds better in idle but you buy that with an annoying drone during longer distances at 3.000 RPM. What is your opinion? By the way: You only can hear the full sound spectrum with headphones 1969 Mustang Mach 1 Engine: 390 cui / 6.4 l (Ford big block) Color: Gulfstream aqua . . . . . . #firstmus