Installing:
If you are running the steam (online) version, then paste the gamedata and uidata folders into your main evo directory.
(i don't use steam, but it's something like C:\Programfiles\Steam\steamapps\<<yourusername>>\GTR Evolution\ - you should be able to work it out
)
If you are not running the steam version (offline), like I do, it depends on what the mod is for. I
think If the mod was a Race07 Mod or Track, i.e. F1 2005 or Crowne Plaza Raceway, then Paste the gamedata and uidata folders in the root folder of GTR Evolution, C:\ProgramFiles\Simbin\GTREvolution. If it is a track, often you will then also have to go to gamedata\locations and paste there.
If it was a mod or track Intended for GTREvolution or RaceOn, i.e. the Saleen Mustang SE Cup or Brianza Addon, then I put it in C:\ProgramFiles\Simbin\GTREvolution\Addons\GTREvolution\ Directory (note the addons folder) and then paste the gamedata and uidata folders there.
This is My experience. Hopefully it works for you.
Lamborghini, Ferrari and Porsche:
Ferrari and Porsche:
Your best bet for the Ferraris And Porsches is scca1981's 997GT3RSR and F430GT2 mod. This adds those 2 cars to the GTSport category of GTREvolution. Available in the Downloads section Here at racedepartment.
There are also these other mods:
http://hsw.hu.ip10.varolista.hu/index.php?headlinesid=15561&lm=800
http://hsw.hu.ip10.varolista.hu/index.php?headlinesid=15383&lm=800
http://hsw.hu.ip10.varolista.hu/index.php?headlinesid=14146&lm=800
http://www.artsonika.com/index.php?option=com_remository&Itemid=27&func=fileinfo&id=239
Lambo: Your best bet for this is the GTR2 for GTR Evo mod. It is the only one I've found with a lambo. Just search it on google.