Not the final build of GT6 in these videos, just the old prototype demos doing the round of game shows
The Pagani doesn't have an engine sound, they removed whatever it had there before - just a place holder for now. All you can hear is the turbo and blow off valve
They have a new sound engine system in the works, but it will probably be patched in after release. Unless it's already done - but PD have not released any info and only a month to go...