GTT=XRG GT Turbo, what we use to call the XRT back pre S2 release (S1 and S2 demo). My skin for the XRT has a GTT "emblem" on it.
As for the really long boring large straight oval track, I could care less. I can understand why some folks would enjoy having it. "Test" tracks would be interesting to play with offline, but not for racing. But since the focus is with "online racing", I doubt the devs would bother with this.
The current oval can't be compared to a high speed test track. Even though you can run around with the throttle pedal floored for the entire track, you still scrub speed off around the turns. For testing maximum top speed, you need very very long straights so you can wind it up with a high gear ratio. A gear ratio that would bog down greatly entering into any turn.