This happened to me. I tried multiple things and couldn't get past the loading screen, even after switching to a backup with hybrids, then another backup that had no modding on it whatsoever. I ended up deleting the profile from my ps3 and starting another one.
I have found that you should do your modding in separate stages. By this I mean, you can use 1.3.1, 1.5a, and/or 1.6 then use bruteforce and hex. If you do BF/hex first the garage editors don't like to open the files sometimes, and you would have to enter the game, play with your cars, then go back to a garage editor afterwards.