Creating Skins (support closed)

I know this is in the wrong place but support is still closed.

Thanks for any answers people very much appreciated!

Right I’m not great with technical stuff but I can usually muddle through (with a few pointers). I want to create my own skins to put on the GTA 4 cars, I going to use Gimp but I can’t find the layout of car with all the different panels to put my designs over. Is that something I have to download or is it in a file somewhere on my PC? Does it make any difference that I have the game on Steam?

I’m assuming I can only have 7 types of Police vehicle as that’s how many are available on LCPDfr but I am assuming I can change them, say the noose truck to a Landstalker I would design?

For example the 7 cars I would want would be:

The four standard police and noose marked cars (all with my own design)

Then replace the FIB Buffalo and the two vans with a Turismo (marked), Landstalker and plain Police curser to be unmarked undercover cars.

And is it worth getting ELS? I want to play around with creating my own lights but intend to use manly blue and the current ‘blue’ lighting is more white than blue

Thanks for any answers people very much appreciated!