Other bonuses include unexpected effects if your car / train is damaged while travelling through time or perhaps the nth dimension. Unfortunately at the moment this appears to be only changing between different times of the day, although it does include very similar effects to those seen in the films when either reach 88 Mph.
This modification is obviously based upon the Back to the Future films and includes the Delorean, an Unmodiffied Delorean and the Steam train, both the Delorean and the Steam Train can fly as well as go back in time. Here is the Back to the Future: Hill Valley modification for GTA Vice City.
