Hi,
Re-installing GTL should not affect your personal settings as it does not overwrite them. Your settings are stored in folders with your 'Profile' name you are using The 'Profile' name is the one you give yourself on the game. When yo have re-installed the game any 'Profile' or 'Profiles will show up again just as you left them with the same set ups, money, replays etc.
Perhaps what you are doing is deleting all the GTL files and not unin-stalling the game using the program itself.
Regarding the Auto Update, did you realise that the files downloaded are both the unzipped (all cars & tracks downloaded and stored but not installed) and zipped (all cars & tracks downloaded and installed). I do not know which one of these is recognised by the Auto Downloader but if you are only deleting one set then perhaps the Downloader is seeing the other set, so it thinks you have all the files needed.
I hope this jibberish is clear enough for you

, however, should you be in need of further jibberish

do not hesitate to ask.
Happy racing on this the best GTL site ever!
