I managed it with this:
ABS: 1
TCS: OFF
STM: OFF
Skid Recovery: OFF
Line: OFF
Tires: Racing Hard ( I imagine racing softs would make life a lot easier if you're struggling but I won all races using racing hards and wets when necessary)
Gear ratio 'Top Speed': 246~250
Won all races apart from the last one because I didn't do it.
you wont out accelerate the AI, they seem to be set to have the perfect position between traction and the edge of loosing grip under acceleration so just use the extra top speed and draft them on the straights to nail them in the corners.
If you're struggling with wheelspin don't turn tcs on but just exit the corner a gear higher, you'll loose out in acceleration but you can gain it back on straights/corners/braking.
It just takes consistency more than anything to be honest, I knew where I was quicker on Fuji (sector 2) so I just went for it through there and cruised the other sectors.
Indy was relatively easy (won by 20+ seconds thanks to the long straight and top speed advantage).
Monaco was a little more tricky and can be problematic if you can't maintain a good pace (probably hardest of all of them).
Nurburgring I just cruised as the AI constantly span on the chicane for no reason.
Monza the top speed advantage once again brought about the win easily (you can cut corners too if you're struggling)
Suzuka I don't know about as I didn't bother to do the race.
Hope this helps a little
(Also, car had chassis rigidity upgrade from the tuning parts, oil change and that was all, the car only had <200 miles on it from the dealer so I didn't think a chassis refresh or engine refresh was necessary)