[O3 subaru WRX]

ok so, im pretty new at this but...

is it good for a 03 wrx to have just an uppipe with no cat system?
i heard from someone that in the 06+ wrx models that they took out the cat system and just had an uppipe (2.5L). but im not sure if the guys car im looking at is trying to convert to this system with an 03(2.0L).

if additional parts are needed.. downpipe, cat system... let me know, im just trying to figure this out right now