You have all kinds of options, muffler options as far as brands the main ones are Flowmaster, Magnaflow, and Gibson. Rather than buying an exhaust system you should just buy a muffler online or wherever then take it to an exhaust shop where they weld it up for you rather than just using clamps.
As far as deep throaty sound, I'm gonna say Flowmaster makes the deepest throatiest sound, especially compared to the Magnaflow which I have right now and is not very loud. Flowmaster single chamber 40 series would provide qutite a grumble.
For pipe sizes, stock on mine was 2 inch, you can go anywhere between 2 and 2.5 inches comfortably. 2.25 would probably be ideal and would just open it up a little more.