Try slipstream on 50.
I have it on from 50 for macca and ferrari to 10 for aguri.
So the backmarkers are easier to overtake if they dont move, however following Mclaren, Ferrari, is tougher, losing grip-
GPGSL career;
Current team:
Team ShadowSubaru,
Previous teams:
MPR, Minardistarts:100
Wins: 12,
Podiums: 34,
Fastest Laps: 14,
poles: 12
Points: 708
winner of Belgian GP (s1), Australian GP (s1), Canadian GP (S1), Brazilian GP(s4, s5), Hungarian GP(s3), Italian GP(s3), French GP (s5,s7), Monaco GP (s4) and USA GP