What can you do to avoid unnecessary noise?

The selected combination of avoiding high engine revolutions and not modifying intake and exhaust systems is correct because both actions contribute to minimizing noise pollution. According to German traffic regulations, particularly under the law regarding noise emissions from vehicles (the Straßenverkehrs-Zulassungs-Ordnung), it is important to operate vehicles in a manner that reduces unnecessary noise to respect environmental standards and community peace.

Avoiding high engine revolutions helps in keeping the noise levels down during operation. Modifying intake and exhaust systems can significantly increase noise levels, hence why this is discouraged. On the other hand, removing fairings does not have a direct connection to noise reduction and is irrelevant in this context.

Focusing on all relevant options when addressing such questions helps ensure adherence to regulations while promoting safety and environmental considerations in traffic.