I have the black 787 with turbo-4 (of course); using it for the Sarthe Endurances, I beat the Sauber Mercedes to win Sarthe II.
This car is a rocket! 360 kph!
I Have a problem of running out of gas before my tires wear out, though; even on R3 / R2 ..
This is the tune I use:
All the upgrades, springs at 16, height at 65, shocks 5/7//6/7 (bound//rebound), camber 1.5/2.0, stabilizers at 4, brakes at 8/9, DF 57/80, LSD 12/32/22, gears: Auto-14/Final=3.5, TCS=4.
Great speed, great handling. Can even reduce to turbo-3 and still smoke most any other car on the track.