I fail to believe any Civic sounds better than any boxer.
You'll want to replace the Prodrive with a new axleback, or more likely, a new catback exhaust.
A downpipe would be great for sound and performance. It will add some power, but you MUST get proper engine management to go Stage 2 to run it. But it still won't be all that loud.
Check out Youtube to get an idea of what's out there. It will give you an idea on tone, and relative sound, but obviously won't be near as good as hearing it in person. See if there are any locals or meets near you.