The mods he suggested will also change the tone of the exhaust. A cat is restrictive, removing that can enhance the exhaust note quite a bit and help out those borla mufflers. Your best bet to make it louder and mean sounding would be headers and a full catback exhaust.

For a slightly louder exhaust, those mufflers alone will be good, but mufflers alone may be a little raspy or high noted instead of a deep throaty sound. To change that, replace your resonator with a glasspack, they're cheap and they help out quite a bit.