A) Find a large resonator for (deeper), less sound, smaller resonator or no resontor for as loud as possible. www.bigexhaust.com is a great place to start. If you don't know, a resonator is just a muffler that has the same size input and outputs. The uglier, the cheaper, the better.
B) Pick a muffler. Again, the larger the muffler, the less sound, less rice. Same link for the muffler. Then find a tip for your muffler, either at an auto parts store or online. The muffler shop that installed mine had dynomax mufflers in stock which are pretty quiet. If you talk to them, they should be able to tell you which ones they have that will kill off any rice noises or droning. Make sure the tip fits the same size output of your muffler.
C) Call around to local muffler shops and ask if they do custom work. Franchises like Meineke and such will NOT do custom work, so you have to open the yellow pages or search www.switchboard.com for a mom and pop shop that will do it. Cheap.
D) I paid about $100 total for labor and parts (not including the $50 resonator and $80 muffler) for them to start at the cat, and cut out all of the old piping. Then had it replaced with either 2.25 or 2.5" pipe all the way to the back (they will insert your resonator or muffler at this point as well). As for the diameter to use, ask around in the forums. Some people like 2.25" and some like the 2.5". More low end power and torque with the smaller diameter, better MPG and top end speed with the larger.
I personally went with the 2.25". Its loud because of my header, but doesn't sound near as bad as it did before I put on a larger muffler to kill some of the sound off.
Any 4cyl engine is going to sound a bit like a Honda with the SARS virus, but this doesn't sound too bad at all. I think you wil be pleased, especially since you don't have a header on your car.
I was kidding around, but I don't have mine mandrel bent. Mine is below, and as you can tell its pretty much straight back. The curve that is in there is not severe enough to hamper the output. It looks bad, but if I had a picture from the other side, you could see what i'm talking about.