The car started making this horrible noise at cruising speed of about 35mph (60km/h). I feel like the car shifts up too fast as I'm in 7th or 8th gear by the time I reach this speed. Car also feels different, like if it's lugging. It's weird, doesn't feel the same anymore overnight.
Research has sent me on a goose chase of potential things like adding a weight on the AC hose (although that was suggested for n55 engine), replacing the crankshaft pulley, vibration damper, motor mount issue, etc.
The car is a 2015 428 xDrive GC with about 105k miles. Automatic transmission with n20 engine. I'm always regular on maintenance, and 91 gas only.
What could be causing this issue ?