Absolutely not. Exporting used cars requires clear proof of foreign currency receipts in USD/EUR (water bill) to be provided to the Chinese foreign exchange administration, customs, and tax authorities for document verification. Cryptocurrencies are considered illegal settlement channels.

We will honestly inform you of the common issues with this model (such as the water pump failure in certain German cars) and show that this car has had the improved parts replaced.

No, this is a serious customs violation. Complete vehicles (HS Code 8703) and auto parts (HS Code 8708, etc.) are subject to completely different import tax rates. Combining them on one invoice could lead to the invoice being returned by customs and may expose you to tax fraud accusations at the destination port.