World Touring Races PP800
There is no trick and no secret.
The only thing to consider is that these races only require racing tyres and a car with not more than 800.00 PP.
Which means you are free to either
play it fair (WTC 800 Lake Maggiore as this my favourite track).
This is the WRX Gr.3 as comes from the brand central, on medium tyres, 722PP
Or simply pick a car that is naturally closer to 800PP
This one brand central, medium tyres, 796,61PP
Or you can go above that and downtune cars that are above that limit
lowest downforce, as downforce kills your straightline power and fuel, then reduce power as much as necessary.
I guess the Porsche would be better suited for this kind of event as its hybrid system is superior.
Or you can pick a road car and try out different things
Some will be good, some wont work as well.