Well,
The bottom-line in this as in most mods is how much are you willing to spend? The Screaming Eagle, modified my mainstreet motorcycles (see login page) is a top choice by riders in these forums, however as the V-Rod is entering into its 4 year, there are several aftermarket exhausts available, but again it is what your account can handle!
You will need to either get the matching flash sold by the MoCo for your exhaust setup, or get a race tuner or power commander (do a search on these)
This motorcycle will work your pocketbook, so just be prepared!
Mike