Need Exhaust Recommendations

I absolutely agree. 2.5 inch system from one of the above vendors, plus a couple bucks at the local shop, to make the manifold to intermediate pipes, and you will be golden.
2.5 might be slight overkill, but it will allow it to breath, and it should handle just about anything else that might pop up, such as a larger, better breathing engine (408 Stroker, MMMMM)