What would give me the best free flowing system?
"Best" by what measure? Flow (straight 2.5" pipe - back pressure isn't needed for low-end torque on 1.3L / 1.6L engines because there's enough restriction in the exhaust valves already), exhaust tone (depends - do you like quiet, loud or somewhere in between - if so, where in between?), price (I covered this in post #4)?
The most common setup is usually a 2.25-2.5" cat-back system with a muffler that fits the person's version of "good sounding" exhaust. Turbo mufflers are popular (free flowing, but louder). I've already mentioned the V6 muffler option (good for free flowing & quiet). There's another muffler gaining in popularity due to it's price & construction, but I can't find the link (generally sold on e-bay, reportedly sounds good & is build stout).