Inside the echo freehub Is pretty much the same as the profile as there are the same amount of engagements and the internals look very similar. The reason why they were breaking was that the Ratchet was glued in making it break easier under higher loads. As people love Pro2 hubs I thought about the idea if having the profile internals to make them compatible with mod bikes. As It is harder to get profile hubs in 32H (standard in trials nowadays) and also harder to get one that will take a disc too it will probably be easier, if you have an old profile, or the shell in your profile has cracked or whatever just to get a Pro2 hub shell off tarty and put in the Profile internals.