Need For Speed Hot Pursuit model swap

[LesterModdingGT]

Note: I am focusing one the original, not the remastered.

So I am new to this kind of scene and I need a little noob help. It's like a simple car swap (like changing a charger to a 370z as a example) from the game itself. So what tools I need to use in order to achieve this and how complicated is it? Since I wanna change the cop cars during the chase in Hot Pursuit mode and that's why I wanna do it.