I am 4000 miles in with the Dinan exhaust and the droning has decreased slightly but still noticeable. I am also interested in how long it took before it goes away.
12 550i xDrive (Dinan S4, Intercoolers, Exhaust, Springs/Shockware, Negative Camber/Low Compliance Rear Control Arms & intake on order; 3M CR40; AG M355, Michelin PSS & Tikore Ti Lugs) - Alpine White, Beige, M Sport, Cold Weather, Premium Sound, ARS, Sport Auto, Power Shades, Side/Top Cameras, HUD & BMW Apps.
13 Infiniti JX35 AWD - Midnight Garnet, Deluxe Touring, Technology, Theater & Premium Packages.
07 E60 550i Dinan S2 & Intake (Gone)
09 Hyundai Genesis 4.6 (Gone).