One of the guys I ride with has the V&H 2-1 on his Road Glide, and it sounds really good! Nice rumble at idle, and definately loud on the road or opening it up!
The V&H will definately get you more power than the Samsons, if you can handle the 2-1 look (which some people can't, to each their own!

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Since a stock Harley doens't really have a ton of oomph (something like 60ish hp or so), I wouldn't put the Samsons on a stock bike. If you're upgrading the engine to 95 or 103, then those wouldn't hurt you as bad.......