Forza replay only improves the car model slightly and adds some post-processing effects, and a higher quality AA, not to mention that the game was developed with 60fps in mind, so obviously it won't have assets that could have been used with the extra 16.6ms. Synth already said this some pages back, see if you can find his explanation.
I'm sure others have noticed this, but you can get the "gameplay" model of cars in screenshot mode.
How? Change the focus (literal focus of the camera) to a car that you're not initially taking the picture of.
This is a shot of a gameplay model (see edit below)****and not the higher-polycount "Forzavista" level model.
This is also a "gameplay" model. The camera isn't this close during gameplay, so you wouldn't notice things you do this close.
It's a neat trick to basically taking "gameplay" level shots with a free camera.
Edit**** See post after mine....it could be an LOD one step down from the players gameplay model.
If I were to hit "X" (focus) on this car before taking a picture...it would completely reload and re-render the model..lighting and all.
Ooof, I thought it was slighter than that. Are you sure non-primary aren't downgraded further in gameplay? Because I don't see those low polygons when I'm in the chase camera. Chase camera looks very close to Photomode models for the primary car.
You may be right...it could be ONE LOD lower. How close is the lower chase cam? I'm not where I could test it on the non-focused photomode cars.
It's possible the car you are actively driving is an LOD between Photomode and the AI cars. This is a graphics thread, this would be a neat thing to figure out.
I agree, when swinging the camera around your car in gameplay, you don't see polys at the wheel-wells.