Bahh... I thought there was some new news on FM4 for a minute..
This is my 'educated guess' on Kinect and FM4 from all the info I've read around the web.
It's based on the many developer articles that say that Kinect is a set of libraries, which ones you use depends on how much 'CPU/GPU' time is required to process that feature..
So, if they are intelligent, I see 3 scenarios
1. The new car exploration - Uses all Kinect's main tracking features, and no doubt it'll be 30fps (or less) for sure.. it's all about graphics fidelity
2. Using the virtual wheel kinect style - unless this is limited to specific modes (over taking challenges, one on one head to head, I can see this eating into any 60fps target to some degree, so I'd expect less then 60fps, not sure if T10 would do the same as it's rivals, i.e. claim 60fps, but have it dip dramatically and be quite variable. And since it doesn't need full body tracking, just upper body/arms, that automatically should allow them to possibly use it in normal game modes with not too much of a hit..
3. Just head tracking in-game, normal controller/wheel - Using Head Tracking is probably almost no overhead in processing terms, and I'd expect 60fps as an achievable target.
So kinect doesn't worry me, the modes where it's actually going to be doing some processing is modes where 60fps isn't paramount, and that's fine by me.
To be honest, it's more the 16 cars that worry me..
I've been playing more Race 07 / rFactor and just about to dip into iRacing, and despite some pretty 'safe' physics params, I still like a lot of the feedback and nuances that you feel in FM3, it just needs to take a step on viscerally, and I mean in the physics params, not the NFS Shift rubbish (It's a great game, I have it on PC, but had to mod it to turn off all of the visual fluff)..