I had a little test with the "Force Setup" function and it seems it is just working half the way as it should. What i tried to do is to force specific upgrade in multiplayer. So i went into SP, choose the track and car, made the upgrades i wanted and hit "Force setup" Button. I copied the .ini which was created to the dedicated server, deleted it from my local PC and started the server. Back at my local PC i startet the MP, connected to my server, choose different upgrades than allowed on the server. On the server as expected i didn't had the upgrades i choose but those which were set in the .ini. Now i left the MP went back to SP choose again different upgrades than allowed on the server with the same car as in MP, loaded the track, exited SP, went back to MP and straight entered the server without changing the upgrades and now i had those updates on the car which weren't allowed on the server.
I might be totally misinformed and if so please excuse me. But doesn't force setup only apply to the AI cars?