Fully functional 4x4 car chassis. The assumption was to build the lightest and smallest possible suspension with Power Functions elements. It seems to me that the goal has been achieved.

LEGO® Power Function elements used in this chassis:
#87513c01 9V Battery Box
#99498c01 Motor 9V Servo
#99499c01 Motor 9V L
#58123c01 Receiver Unit
#64227c01 IR Speed Remote Control
Download:
4x4 Small Chassis No.7 RC
Complete project
BrickLink Studio IO file