Modification Makes difference in cars performance

When cars are designed by manufacturers they are based on concepts, they have for designing that gives better performance but sometimes it does not work and need further modifications, in such cases is it affect the performance of vehicles as we disturb the design of vehicles and would not match the designing concepts that were in the mind of manufacturers .

Many youngsters change their cars to modify because they can make car as per their use like they can make fastest car by modifying it but it can't give more mileage. Many other things can be changed by modifications like colour, size, designs and so on.