I've now played Forza 6 Apex and I'm very impressed!
I was a bit confused by the GFX settings initially because it defaults to a Dynamic Rendering system which basically means the game engine adjusts things on-the-fly in order to maintain optimum framerate.
For many users I reckon the best option would be forcing your chosen resolution and target framerate (you can choose from 30fpps, 30fps locked Vsynch, 60fps, 60fps locked Vsynch, unlocked) and leave everything else Dynamic.
Then the game will downscale things like particle effects and shadows as and when needed to maintain your desired frame rate.
It's a clever system and one I wish more games would adopt.
Or you can just force your settings manually.
Thankfully you can enable a fps counter so you can really see what you're doing when you tweak.
On my PC I was able to force everything to Maximum @ 2560x1440, and with 8xMSAA and the unlocked framerate I was never below 70fps and usually about 90-odd and often topping 130fps.
This was in a race with 15 AI cars and I was driving in the cockpit.
Birdy's description of it being like Gran Turismo is spot on. Real-life cars on real-life tracks and visually very impressive.
The only downside, for me, is that the game doesn't currently support wheels. The developers plan on adding wheel support in a future update.
I look forward to it...