The vibration isn't anywhere near strong enough, thats why you can't feel the rear end come loose.
Like I said before, there is a huge uproar about it on forzamotorsport.net so I see it being patched by the time the game comes out.
Only saw 2 skylines on my trip to the sydney 'burbs.
Black S1 33 with green P Plates.
And a Grey 32 parked at a house with a black JZX100, blue DC5 and something else.