Your answer can be found in my previous post which I will quote here.
Veriest1 wrote: As competition increases technology will also increase with each team trying to get the edge on the competition. It is no surprise that drift cars (at least this one) are taking cues from their road race brothers where chassis, engine, suspension, and aerodynamic technology are just a step or so down from Formula 1.
PGBrian wrote:this is sort of on topic.i was talking to Miki san (Top Secret D1 driver) last friday and asked him about the wing he had on his old s14. i noticed that sometimes he would leave it off for certain events.iasked him why he did that.he told me taht on some courses, it simply gave too much downforce, and was making his runs not as good as they could be.
just FYI stuff.
Ooh! I had forgotten about that. This could/would be a function of the tires versus the smoothness of the track surface and the camber angle of the corners. I'm sure weather, possibly humidity and general temperatures, may play a part as well.