Is it permissible to buy a car in installments with only a customs card, without obtaining license plates, and then sell it to benefit from its price, and is it permissible to sell it to the same showroom from which I bought the car while it is still in its place?

Purchasing a commodity and selling it to someone other than the original seller to obtain cash is called "Tawarruq," and it is permissible according to the majority of scholars. Requesting a third party to purchase a commodity and then sell it to you in installments is called "Murabaha for the one who commands the purchase," and it is permissible under two conditions: that the company buys the commodity for itself, and that it takes possession of it before selling it to the customer.

Therefore, it is not permissible for the company to sell the car before taking possession of it and moving it from the showroom. This is the preponderant opinion on the matter, and it is the view of the Shafi'i school, and the قول of Abu Yusuf and Muhammad from the Hanafi school, and one narration from Ahmad.

Moreover, there is no harm in selling the car without going to the traffic department and obtaining license plates after taking possession of it, because these procedures are for documentation and are not a condition for the validity of the sale.

It is not permissible to sell the car back to the showroom, as it is a form of deception to engage in usury, and this is what is known as the "triple stratagem."

In summary: The company must genuinely purchase the car and move it from the showroom before selling it to you, and you are not permitted to sell it back to the showroom itself.