I've struggled to follow this thread, so I don't really know where we are. Apologies in advance
The way I see it is that if there is a large gulf in gameplay (racing) between the standards and premiums, then PD probably won't put them together.
The lights are a non-issue, since the high / low beam thing is probably only about graphical representation (two-stages of "illumination"
on the actual car, whilst the Standards only have the one, and PD can't justify going back over them to add the second level).
So, the Standards only have one level of lighting (at least as far as the car
appears). However, we've already seen the LoD switching at LeMans at night where cars around the player use "high beams" and those further away switch to low'uns. This behaviour should extend to the Standards, whose default setting would better be full beam, rather than dipped, for obvious reasons. All this means is the
projected light will change, but the car will still appear to be giving full beans.
If PD really are so fussy as to not allow the LoD to affect Standards, then that poses a serious problem, doubly so since the Toscana video only looks like low / dipped lights.
Another issue, one that Devedander mentioned, and one I've been thinking about for a while, is bits dropping off cars. But, as far as I can recall, this will only apply to certain cars anyway (i.e.
not all Premiums - it's a three tier damage system, not two.) We've only seen Premium rally cars with doors flapping and / or missing.
Maybe this is partly because of the Standards and this behaviour will be disabled for mixed-tier racing.
And what about the horn? I'm sure they recorded the horn sound when they did the engine / exhaust sessions, though.
Tuning is a bigger issue, frankly, since GT5 appears to be using a new system (going by the exhaust section screenshot from earlier in the year) so it might be the case that Standards use the old, GT4-style tuning / parts - though hopefully this shouldn't have any effect on the mixed-tier racing issue.
Additionally, I don't think mixed-tier racing should be prevented by simple, cosmetic / aesthetic reasons. Maybe PD feel differently.