What we know so far:

1. Requires +11.2 PR over base car. (126.8-127.2)

2. Maximum available tuning is 8-5-8-7 giving ~+8.9 PR and is very similar to British (8-7-7-6), Austrian (7-7-6-8)  & Abu Dhabi GP (8-6-6-8) tuning packs.

3. The extra 2.3 PR has to come from driver and TP level ups. 

4. Rewards are M$ 200,000, 50 GC, USGP Tuning Setup & a 2020 Season f1 car of player's choice. You need to complete the GP within 5 days to earn the car or you get the other rewards but not the car.

Some numbers: