Mazda 6 Service Manual: No.20 noise occurs at idle when vehicle is stopped in all positions/ranges

No.19 excessive shift shock on torque converter clutch (tcc)

No.21 noise occurs at idle when vehicle is stopped in d, s, l ranges, or in r position

Other materials:

Mazda 6 Service Manual: General procedures
PRECAUTION (SUSPENSION) Wheels and Tires Removal/Installation When a wheel is installed, tighten it to 88-118 N·m {9.0-12.0 kgf·m, 65.0-87.0 ft·lbf}. Suspension Links Removal/Installation Tighten any part of the suspension that uses rubber bushings only after the vehicle has been lowered ...

Mazda 6 Service Manual: Mazda Radar Cruise Control (MRCC) (Some models)
The Mazda Radar Cruise Control (MRCC) system is designed to maintain headway control*1 according to the vehicle speed using a radar sensor (front) to detect the distance to a vehicle ahead, and by presetting the vehicle speed between 30 km/h (19 mph) and 145 km/h (90 mph), the driver is freed ...