Who can help me with installing the 2018 cars

I currently have the 2016 mod of gp4forever. But would like to have the 2018 cars in my game.
I know that I should use the wadupdater and first unpack the cars.wad.
Do I have to remove everything that is in the mudflats and stick everything from the 2018 cars into it?

Who can help me thankyou

for me i use easywad ,and open the cars.wad with easywad

look here for many of the questions you have
[www.grandprixgames.org]