The grip mode tests the car in acceleration, braking and cornering abilities. Therefore, a car doing well in all these categories should be chosen for this mode. The best car I have come across for the grip mode is the Porsche 911 Turbo. As soon as you start your career, you won't have enough money to buy it, instead opt for the Mazda RX-8 which is very good in cornering at high speed without braking too much. The BMW M3 E46 suits very well the grip mode but later in the game like the RX-8, it won't be able to compete with cars having greater acceleration and speed. This is where the 911 Turbo comes in help. When tuned, the 911 Turbo does 0-100KM/H in 2.7 seconds, 0-160KM/H in 4.5 seconds and has a braking distance of 28 meters from 100-0KM/H. the other car you can pick is the nissan gtr r33 it is better stock but you will need to fit the widebody to have the best performance from the car it is an absolute beast i beat a porshe 911 turbo by 1 minute in the third showdown on the autobahnin this car.
Turn ON Best Line and Turn Indicators in the Interface menu and start driving. By following the Best Line, you can be sure to reduce unnecessary braking and steering during the race. When the Best Line turns red it indicates that you must brake and start cornering. This line is the best a car can take to achieve a minimum time for the lap.
If a wrong car is picked and very badly tuned for the grip mode, you'll be sure to have a bad time steering and at times you'll have to brake and nearly stop the car so that you can take a turn. Some cars take corners as if there isn't any steering wheel in it, while others exit corners very badly, where sometimes it can continue turning and go out of the lap. Tune your car if you know what you are doing, as every single change will have a great impact on the car's performance.