Get the Magnaflows, you will love the sound, run the pipes str8 back(cut the y pipe), and you will love the sound. I did that with my old 98 V6 and lots of people mistook it for a V8. Well I would get the "is that a 5.0L?"
I think the midpipe would give you more top end power than a catback, but you would lose torque down low.