using SCIENCE to ELIMINATE exhaust drone: I FINALLY did it! - YouTube
Exhaust Drone: What Is It and How to Eliminate It? – Pertronix
Exhaust Drone Removal - BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)