Uhm. You can drive the X2010 around Indy easily without lifting even with Racing Hards. How do you arrive at producing such a variance in times? You should be able to do every lap within 3 tenths or so. (disregarding traffic) I guess you can play a little with the transmission, because 7th is a little long, if you're running by yourself. With slipstream you might need the long 7th though.
Myself, I don't even understand why bother with the X2010's setup. Even a Level 0-Bob cannot lose a race in this car and driving it myself is just stress, and no fun at all.