I think at this stage, given that there are now so many variables being stirred in the pot, it's almost impossible to work out where the problem is. However, it is pretty obvious that it is something to do with memory management.

If I were you, I would simply re-install V2.0 standard WITHOUT HiJack or any other third party problem. If the problem persists, then it is likely you have a hardware problem and we can begin a diagnostic. Whether the problem lies in the car, or the player, we have yet to determine. But until the number of variables is reduced, we can do nothing to work out what this is and we are all just scratching our armpits.