overall is the b16 se-r better than the b15??

[nametakennow]

Spinning mass doesn't soak up energy, but moving it does. An object at rest tends to stay at rest.

This isn't like a satellite around the earth, since satellites orbit is based on gravity. Balance shafts are physically connected to the crankshaft.

Even once they're spinning, they still create some level of mechanical drag on the crankshaft, just like accessories (AC, etc) do. That's why you lose power and gas mileage when you turn on your AC. Yes the affect lessens if you're cruising at a constant speed since the engine is turning already, but it still takes X amount of horsepower to spin the AC compressor.

Again, BSR doesn't make more power, it puts more of the already existing power to use to spin the drivetrain. This more efficient use of power would show up on any dyno.

I didn't say air resistance wasn't a limiting factor, I said that it can be overcome with more power. Furthermore, air resistance still has nothing to do with engine power.

Those same race teams spend massive amounts of money on lightening crankshafts.