All depends on what your budget is. For a couple hundred bucks, you could take it to an exhaust shop and have them put on a "high flow" muffler. Magnaflow and Flow Master are two of the more popular brands, but there are several on the market. I have a Magnaflow on my beast. By just replacing the stock muffler with a high flow muffler, you'l get some of that growl you're looking for.
Keep us updated on what you decide and do, or, if you need some more help.
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