Because of the online gameplay, there is a need to control and balance the performance of cars. It is likely Performance points will make a return. Quick tune has always been there in Arcade mode, GT5P was sort of a cross between arcade and GT modes as we know them. There will be a full GT mode in GT5, without quick tuning.
Eiger and London are both confirmed, and the likelihood is we will see full length circuits, Eiger and London in Prologue are both short circuits (London because it has no pitlane, and Eiger because i think it stated that in GTHD, also it has roads leading off at 2 points which imply a longer layout).
The F2007 is likely to make a return, as will all the cars in Prologue, unless PD have some licensing issues (Which is doubtful, i think if the car was in Prologue it will be in GT5). As for whether we will see other Formula One cars, or even open wheeled racers, we don't know. The confirmation of IRL has been confirmed to have been false, but we may see at least some Indy cars in the game (I mean with the addition of Indianapolis, and the potential to have an unofficially licensed Indy 500 race in the Endurance hall, how can we not have at least one Indy car? Even if its a fictional version like the F1 cars in GT3 and 4)
The concept by GT cars, are likely to have just been demonstrations of the tuning potential of cars in the game. But as with most things, we know very little about it as Polyphony Digital have been very secretive about the details of the customisation features in the game. So we just don't know unfortunately.
As for my request, I want challenging races like S-10, I want the AI to keep up a decent pace and give me a run for my money without me having to pick a vastly inferior car - Like you had to in GT4. I also want there to be two seperate physics settings like in Prologue (Which is pretty much confirmed, the Time Trial Demo was locked to professional in the options menu, which means there is going to be a choice in the final game).
