That kind of class takes a mid level money class (what 2.6 used to be) and makes it a deep pockets class (which it is now). And regardless of which class (other than an "unlimited"), limiting it by driveline is a road to a slow death of a class (just look at your pulling history books and what has happened to gassers and tractors in other areas of the country).
If you limit by power by drivetrain, guys can either limit power to save the drivetrain (some will), refuse to limit their power and keep breaking chit (until they can no longer afford it), or keep breaking chit and buying custom part$ and/or new part$ (many overnight to make the next points pull).
Limiting the class by drivelines is a deep pocket's best friend.
Pulling isn't cheap, but give 50% of a class a chance vs 5%. Limit power at the source and not at the ground....
My .02