In order to acheive the time you claim, several things would have to have happened.
You must have cut every corner you could cut.
You must have ridden every barrier youcould ride.
Time and space warped.
In any case, don't register at GT3Times, or any other online database, and post that time, because you will be banned on the spot. A legitimate lap is done in a single player mode, has no contact with any barrier/wall/rock-face and at least some part of at least two wheels must be on the track/rumble-strip at any time.
If you're claiming 48s laps as well, the above also applies, since, as mentioned, the fastest ever recorded legal lap was 48.550 (with the 48.497 currently in the process of being proved).