Subaru 2008 IMPREZA - Manual (Page 265)

Trailer towing
Your vehicle is neither designed nor
intended to be used for trailer towing.
Therefore, never tow a trailer with your
vehicle.
SUBARU assumes no responsibility for
injuries or vehicle damage that may result
from trailer towing, from any trailer towing
equipment or from any errors or omissions
in the instructions accompanying such
equipment. SUBARU warranties do not
apply to vehicle damage or malfunction
caused by trailer towing.
Driving tips
8-15