i recently changed the 4 fuel pipes under the manifold of my 2001 legacy gtb, i took it for a drive after the repair and after about 30 minutes, i lost power and had a fuel smell due to the new pipe splitting and shooting fuel out. is there anything that could have caused this other than a poor quality part. the split can be seen on top of the pipe on the left side

Can't see any other reason than poor quality hose (which would also make the others suspect).
Equally, it could have been damaged during production or during packaging?

Is it correct type of hose, injection system fuel hose for moderm ethynol fuel blends is specific type and carries a SAE code printed along it's length - example: SAE J30R9 for a modern high standard non submursed hose, You do have ISO and DIN standards and you best cross referencing those as and if needed .
Can be quite difficult getting right type/quality aftermarket as majority of common/easy sources likely stock cheapest garbage they can source and a lot will sell you wrong hose as they clueless or just want make money from selling something .
As with most things you buy these days that need quality/design/function specifics you got be fussy on how you source them .

Other things to check would be fuel system pressure being controlled correctly .