o.k. this is what happen to me:
For Stock Car (Normal) you could not set TC on the option. Your rank will show that "7" on the TCS. However, once you go to Tuned car, which you could set the TC to "0". Both of Stock, and Tuned TCS on the online ranking begin to show "0". It may be a bug.
So if you want to show "0" for your stock car on your rank go to Tuned. This is what happen to me. Personally, I don't think Stock car's TC is on "7". It feels like "0" to me.
I also use a G25
happy driving!!