One problem related to rear suspension has been reported for the 2004 Subaru Impreza. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Subaru Impreza based on all problems reported for the 2004 Impreza.
Rear struts stick and will not rebound after a compression stroke. Causes rear to sag and handling feels very loose. Very noisy. Subaru of America know about the problem, which is either a design or manufacture flaw, and does nothing to issue a recall. There are hundred if not thousand of documented cased on the internet of this problem. I have had three rear struts replaced, so far. . . And once car is out of warranty, repair costs are $500 per strut labor included to replace.