Sorry to say but are you in your senses? You are comparing SUV chassis with a CAR chassis. SUV's chassis can be separated from their body by opening the bolts where as on the other hand the CAR's chassis are welded with their body and cannot be separated.
When you change the chassis of a SUV so you have to update your documents and pay an amount of money to the excise department and make it legalize but you cannot do it with your car.
If you are not satisfied with your car so restore it and give a face-lift it or if its already a face-lift version than you can just sell it to someone who will keep a good care of it instead of ruining it.