I keep finding this cheat:

Serpent Mk5:

Get to 380 kph in the Koenigsegg CC and drive towards
the Tortellinis' apartment. On the last hill you will go flying
and with luck hit a paint can labeled "????". This will
unlock a Serpent Mk5 with a top speed of about 320 kph approx.

Where is the Tortellinis' appartment on the map???

Is this a hoax of something? Cannot find the damn thing...

I've already got the mk2...please help.