The exhaust is actually a Magnaflow kit, but... made for the R-Spec. I kind of went out on a limb and bought it from Hottexhaust.com at a discounted price of ~$860 and hoped it would fit. I had actually done my homework and reviewed the shop manual pictures and the lay outs were identical.
It was a near perfect fit, save for a small modification of one of the flanges that attaches to the cat (don't know if this was a defect in the system, or a legitimate small difference b/t the V6 and R-Spec exhaust lay out).
My intake is custom and has been through an evolution. AEM alleges on their website that their CAI fits the 2012 sedan, but that's a misprint. My intake is about as ghetto, albeit tastefully done (imo) and effective, as you can get.
I built it from a few pieces of 3.5" OD PVC, a metal support bracket, and a Rubbermaid office garbage can (heat shield). Take a look at my gallery here or go to my Cardomain site in my signature for some pics. I painted it matte black with hi-temp engine enamel so it looks clean.
Performance wise, I did manage to knock about 4 tenths of a second off of my best 0-60 times in an experiment that was as well controlled as I could manage. It sounds mean (again, videos are on my CD page) and pulls hard through the gears.
I definitely hear you about keeping it quiet. I've been there and done that and I wanted something a bit more subdued this time. I'm currently running cat deletes and I'm a bit unsure if I will keep them. It's far from loud, but there is a bit of drone until you get up to a decent cruising speed.
Hope this helps.