I would recommend the Dynomax super turbo muffler. It won't be stealthy quiet at idle, but it won't wake the neighborhood either. I have experience with this muffler on all sorts of engine designs and sizes and it never gets obnoxiously loud. But if the stock muffler was too loud with the cat removed, then this setup won't be a good fit for your demands. You would probably have to get a cat or two re-installed and go from there.