Well the Carrera track throws me a litlle because I don't know what tyres work best on that and how much a "magnetic leak" motor would have an effect.
If you plan to club race, I would imagine the 917 and GT40 would be a different class to the rest.
I dont have a NSR 917, to compare, I do have a Slot.It GT40 and I can tell you out of the box its a great runner. For club racing it would depend on your motor rules etc as to if the motors in either would need to upgraded. Both of those come with tyres that should be pretty decent, but I suspect you will have a preffered tyre for the track, the club members should be able to advise on that.
Outright pace, the Scaleauto radical is a class act with upgrades .... but we are talking quite a lot. My Radical has set me back over £100 in race trim including the car ! but it and the identical spec one I built for another club member are leading our Open GT/ LMP championship by some way.
To keep prices grounded, find out what classes and rules you have, If there is something suitable for the GT40, then I would say that would give you the most bang for buck IMO.