ORIGINAL: Greg / MO
Totally interchangeable, without effecting tune.
The speed mods just "ramp up" a bit more than the smooth mods, but I shoot bullet holes with either after simply scewing out a couple Allen screws, switch out a mod, and screwing them back in. And loc-titing the screws in, of course!
I didn't realize how easy it was to change them out. Or did you just make it sound that way.
