Hi. Will the next update also update the demo?
And if so, will the demo have more than just the 4 cylinder engine in it?
If you preorder the game you’ll get I6’s aswell 
The demo will have all the new shiny stuff in it too, yes (all revamp changes), but will still be limited to I4 engines if you don’t preorder. Those who preorder do get the new I6 engines of course.