Get the S-Types, they are perfect. I was worried about being too loud too and almost ordered the Touring. I figured ordering the S-Types I could easily re-sell them on one of the dozen or so Mustang forums.
Boy I'm glad I didn't get the Touring as the S-Types are perfect. Yeah, on cold start they do rumble a bit, but after 10-15s they are a pretty quiet burble. Driving around town normally, you'll hardly notice them over the radio at a normal windows down volume. Stand on the gas pedal and they will loudly announce to anyone around that you are there. At cruise between 60-80, you will not notice them.
They are indeed the perfect mufflers. Also, they are deeper in tone than any video on YouTube will have you believe.
2012 Mustang GT Premium - Lava Red - Lava Red interior - 6R80 - Glass Roof - HID/SP - EP - RVC - RSS - CP - Remote Start
Ordered 4/30/11 VIN 5/26/11 Sticker Online 6/2/11 Build 6/8/11 ETA 6/29/11 ETA2 7/4/11 ETA3 7/11/11 Delivered 7/13/11