C1 Purchase advice

Hello together! I am currently thinking about purchasing a new C1 as a second car and I still have some unanswered questions. At the moment I have a 92 AX 1.4D with no safety equipment. Consumption and repair friendliness are excellent, but it is no longer a modern means of transport. I have a 5-door C1 HDi55 with safety package. I would like to do without climate and factory radio. However, an AHK is a condition! And it starts already… In the case of an internet retailer, there is an AHK for the little one, but according to Citroen, the car is not intended for this. Furthermore, I would be interested in the actual consumption and noise development as well as the quality impression. Does the car have unforgivable weaknesses? Technical shortcomings? Rust is no longer a topic at Citroen… I hope for your experiences. Greeting Dotti