What race in china allows speeds up to 260 km/h on 6.2km of streets?
Guia Circuit:  However, there are two special features that can rarely be found in other street circuits - variation in altitude (over 30m between highest and lowest point of the circuit) and an ultra long main straight that allows top speed of 260 km/h on F3 cars. Guia Race of Macau: The Guia Race of Macau is an international touring car race, and currently a round of the TCR International Series.
i don't know