http://www.rockauto.com/en/catalog/subaru,2002,impreza,2.0l+h4+turbocharged,1378773,drivetrain,cv+half+shaft+assembly,2288
All US guys buy their replacement axles from here, the Empire/EMPI Driveshaft is thicker then OEM and fits amazing. $50 dollars for the axle and about another 50 for shipping still a steal! They also now carry suretrac axles heavy duty version, suretrac is known in the subaru world for their diff they made for the 6 speed.
Also rockauto warranty is awesome.
I bought 2 axles for my 02 wrx and one went bad because I was doing donuts and had the steering wheel all the way turned which would happen with any axles in that case. They did warranty even!