Dual exhaust 2008 Subaru Impreza 2.5L non-turbo

I have a 2008 Subaru Impreza 2.5L non-
turbo(automatic) which has stock dual exhaust.

I need a little more power and was told to get a
catback but am trying to add one that may fit other
models like wrx sti's legacy's, etc. It doesn't matter
which dual catback exhaust I for any of the
mentioned models or any not mentioned I can find;
all I need to know is which other Subaru models
dual catback exhaust can I fit with my model
vehicle and for under $350.00. The dual catbacks
I've found are way too much. I've seen cheaper
dual exhaust pipes for cheaper but for other
models. So does anyone know know if they can
help me find any dual exhaust for other models
that I can I install on my 2008 Subaru Impreza 2.5L
non-turbo/automatic????? I ordered a single
exhaust catback but did some research after
placing my order and have a feeling I'll get less
power even though this part states it fits my
vehicle specifically. Does anyone have any links for
dual exhaust pipes for under $350.00 that are
specific to fit other Subaru models but can also
definitely fit my make and model??? PLEASE HELP,
PLEASE HELP!!!!!!!