We still don't know whether - as I wrote in the article all those days ago - the three cars are new tuning parts applied to existing models or three specific new cars that will appear as "Professionally Tuned" cars along with the other 21 already in the game.
Well, as I stated a few days back as well, if these were additional GT Auto options, why is that not called out in Spec 3? Because it's a significant change to GT Auto, not impossible, but not trivial either. Although, some additions are easier than others. So....
In either case though, there's two questions: why those three cars in particular
...it would be much easier to simply offer a few cars with (player) unobtainable modifications. We've already covered the hero cars. The AE86 very obviously has wide tires, but it does not have the currently available wide body kit, and that combo is not available to players (at the moment). Why those cars? A likely explanation is that there are events that feature those cars.
and are they exclusive to the Power Pack (and why?)?
This is the million dollar question, because the announcement video blurs the lines between the two. Sophy 3.0 is a great example. It's announced in the DLC, but it would be weird for the base game to miss out on that update.
The one possibility that we have not proposed is that the DLC updates the base game for those who buy it, that is totally possible. So, MAYBE, GT Auto gets an update if you buy the DLC. Maybe Sophy 3.0 is offered in custom races if you buy the DLC. We shall see.
Why would they do this??? IMHO, they'll launch GT8 for the 30th anniversary, which means December 2027. That would be almost six years from GT7 launch (Mar 2022 - Dec 2027). The DLC+Spec3 could be considered GT 7.5. The PS4 people have already been dropped for this DLC, and with PS4 support ending in Spring 2026, they may not see any updates past Spec 3.
All I know from those pics is that we currently cannot build those cars