You can't be serious about using a power meter with a non-compatible stem and expecting accurate data. The limitations are significant, and it's not about minor discrepancies in wattage readings. Incompatible stems can cause signal interference, data corruption, and inaccurate measurements of cadence, torque, and other key metrics. It's not just about wattage numbers; it's about the reliability of the data. If you're serious about training and performance, you can't afford to compromise on accuracy. It's a matter of precision, and using a non-compatible stem is a recipe for disaster. There's no trade-off here; it's a straightforward no-go.