dear Hassan, the court ruling that you are referring to was passed only for a particular car. it is not applicable in general. be aware, agents have used this ruling a lot to sell their ncp cars to be used in body change.
when you upgrade your car from an old model to a newer one, body change tax is applicable on it. in your case, you will have to pay around 3 lacs (could be a little less as well) and then and only then your car will be legal.
if customs catch ur car anywhere on the road, it is going to be confiscated unless you have the body tax payment receipts.
if you plan on fighting this rule, please do so. you might be able to save money but be prepared for at least a year's court fight consuming a lot of time and resulting in ruining you car.
once the body change tax is paid, no one can stop your car.
i have paid da tax of a crown and that of a jimny as well. jimny was stuck in customs yard for 10 months coz i also had the same thinking as urs.