Additional to the previous post.
I feel like just about all advice/strategy provided for these races has all been rendered useless by the recent updates. Or maybe the people winning these races don't have the AI set to hard? :ouch: The difficulty setting has no impact on these races. It's for world circuit races. I have used...
www.gtplanet.net
The setups there are
quite old in terms of the game version and lots propably will have seen changes for the better or worse.
But the Stratos is almost a safe bet, as far as I remember it only ever was reduced in PP so in fact should be faster.
The Gr.3 races have become much slower over the course of game updates.
Red Bull Ring likely is more difficult now (but was comparatively easy before) because AI was improved in rainy conditions.
Maggiore is less difficult now (as the AI has become worse on pit strategies, but this is
not conistently the same).
The Mazda Miata Cup can be very difficult, especially as it already was quite challenging and only has been made more difficult (same as Red Bull Ring)
BAC Mono isnt difficult once you can handle the car, but I dont like that car.
The other races with a free choice of cars
can be overpowered with a good tune, though they are possible with quite a large selection of cars.
I have not repeated any of them recently (except for Maggiore), but as far as my general understanding of the changes goes, the Stratos should still be above average because it is both easy to drive and doesnt require much time in the pits.