96legacyoutback

hi there everyone im new on here just bought my first subaru getting it ready for inspection. . . .its a 96 legacy outback wagon and its throwing two codes. Th e first code is p0400 and the second is p0420. the car is running relativly well only bad symptom is a slightly low idle but nothing to alarming. since the codes are egr system exhaust recirculation flow and cat efficiency below threshold bank 1 could these both be caused by an exhaust leak between the engine and the cat because i suspect there is it certainly sounds like it? i just want to be able to set my priorities in fixing it and if the exhasut could solve these codes than i will fix that before replacing other components.