After some research I found that a complete cat-back system is really not needed. Most people have good experiences with them but the stock exhaust provides plenty of flow, so I decided to save myself some $ and just swapped the HUGE stock muffler with a Borla XR-1.
I can't speak for the magnaflows but from searching the forum it sounds like lots of people like the 22" magnaflows best. They do not drone quite as much as the 24" and 18" and are reasonably loud
What I can say is I LOVE the sound of my Borla.
It does drone a tad in 6th gear when MDS kicks in but most always do. I also found the source (tailpipe resonating) and added some high heat, weather proof, sound masking on the pipes and its almost completely gone now.
The Borla isn't loud at all cruising around (anything under about 2500 RPM's) but when you stomp on it....boy everyone knows whats under the hood! Love the deep growl it has. I'll have an exhaust vid for it soon.