Proposal to insert new Part C providing guidance for the application of UN R155 to transformed vehicles. Part C addresses identification of cyber-relevant transformations, impact on original vehicle architecture, connection risks, and impact on cyber security management systems. It specifies that transformations require new approval unless the manufacturer provides clear evidence that the original approval remains valid, and outlines critical factors and examples of cyber-relevant actions. It details documentary evidence expected from manufacturers regarding functional descriptions, connections with original vehicle types, added components and functions, and arguments demonstrating negligible intrinsic risk.