Duals will flow better @ high RPM and the X pipe will remove some of that rasp. Run them both through a muffler with a deep tone (like a Dynomax Ultraflo) and it should come out deep and mellow.

You can probably save yourself some labor, spacing, and material costs by purchasing the Ultra Flo X (duals cross inside the muffler itself).

This is my Plan C. That is, if I exhaust (LOL) plans A and B and I'm still not happy.