Welcome Jamie
and congrats on the new car.
I’ve no idea what the suspension changes are between 18” and 19” factory specced wheels, it could be anything from minor damper or spring rates, different bump stops or next to nothing.
However I did exactly that, bought an in stock car in 2020 with 18” Richmonds then changed them for (aftermarket) 19’s and happily ran it for three years with no issues.
In some respects it’s a good thing as you get to choose any design of wheel you like and brand of tyre as the factory Bridgestones are pretty hard riding.
I’d not bother with the winglets, they’re ugly, unnecessary and collect dirt.