Hi Cote.
Suppose you copy Saleen suit, gloves and crew files, into content/texture, placing everything as hinted in the rar I provided (Saleen suit folder within content/texture/driver_suit, etc).
Navigate to a Saleen car. Look into the data files (assuming they come unpacked, or you unpack with CM) for the driver3d.ini file, open it, and take not of the driver model. For instance:
[MODEL]
NAME=driver_no_HANS
You will now have to create a skin.ini file, and locate it inside each skin folder.
The skin.ini will shows the game where to get the textures from.
Example:
[driver_no_HANS]
SUIT=\Saleen
GLOVES=\Saleen
HELMET=\Saleen
[CREW]
SUIT=\Saleen
HELMET=\Saleen
To create a skin.ini file, you can gather it from any other car, and change it's content accordingly.
If all of your texture files are in place, and the folder name matches, you should see the driver/crew texture reflected in game.
Once this is done a few time, it becomes second nature.
I've attached a screen to make it more graphic... maybe? lol
Hope that helps!