I've used both the RAD valve and V-Force reed valves. The RAD valve will provide a flatter power curve. The V-Force will usually put a pretty good hit in the power curve. As for actual HP increases, they both provide about the same HP gains. The difference is in the power curve. Pick your pipe accordingly. Jetting is done on each bike individually. You probably won't be using the exact same tune up any one else does, even with identical parts. Sorry MXA "wrecking crew", it's not a one size fits all proposition.