after the most recent update, every single one of my vehicle files has been replaced by default gtav files. Even when i try to replace it, or revert to an older version, i get an error that doesnt allow me to change the vehicle at all. please help!

My understanding is that Rockstar has done this on purpose. Sit tight and cross your fingers for a solution.

I used a 'mods' folder which keeps my default game installation files safe while I install the mods. Here is a guide: http://openiv.com/?p=1132 This kept my vehicle mods from being reset. Probably not too helpful for your situation right now.

This topic has been moved to the appropriate forum. Please post in the correct location in the future.