Advanced TAxation for Cars

Greetings, i am fiddeling around a Problem of a Customer.
The Setup:
The only way the products are shown in this project is over a Module wich is embedded in a Article.
This module shows all Cars listed in a category. The problem i am facing now is that car taxes needs to be declared
depending if they are new, or already used cars. New cars need the price to be shown with and without taxes.
Old cars prices on the other hand only are allowed to be shown with Taxes only.
How is that easy solveable ?

Hi,

If the same module is displaying the both type of cars, so you will have to make some custom code.
Edit the view "product / listing_price" and add a check on the product category, if it's category xx, change the value of the option else:
it require some php skills.