[Slow reaction at drive because the mod]

i've installed a mod called real cars and then the game bacame slow and when i'm driving the car is very slow to turn

what can i do to resolve this problem?

please forvige me, i'm from argentina

[about the backup...]

which folders i must to backup if i want to do a big modding?

...i have IMG tool 2.0, but how i open and replace the sami files and how they serves to?

please forgive me i'm from argentina