What technical modifications to a two-wheeler could result in the withdrawal of the vehicle’s type approval?

The selected combination of options, which includes fitting customized handlebars and changing the wheel/tyre combination, is correct because both modifications can significantly affect the safety, handling, and performance of a two-wheeler. According to the German Road Traffic Act (StVZO), any change that alters the vehicle's design or technical specifications may lead to the loss of type approval.

Fitting customized handlebars can change the rider's control and posture, while changing the wheel/tyre combination can impact grip and braking performance. These alterations can lead to safety hazards, making it essential for them to be covered under regulations that ensure vehicles remain compliant with safety standards.

On the other hand, installing an identical engine does not affect the vehicle's original specifications as it maintains the same model and type, so this action typically would not lead to the withdrawal of type approval. Understanding these regulations helps ensure road safety and legal compliance.