Excellent mod! For those looking for a quick fix to get a higher top speed out of the cars, here's some instructions. If you're using the steam version go here...
Steam\steamapps\common\race 07\GameData\Teams\STCC_2015
in the STCC_2015 folder locate TTA.grb and open it with the notepad. You may want to make a copy of the original file before going further just incase anything goes wrong.
Copy/paste the following replacing everything under [GEAR_RATIOS]
ratio=(10,35) //1
ratio=(7,18) //2
ratio=(16,33) //3
ratio=(16,27) //4
ratio=(25,36) //5
ratio=(31,37) //6
[FINAL_DRIVE]
bevel=(1, 1) // 1.000
ratio=(12, 34) // 2.833
ratio=(12, 32) // 2.667
ratio=(12, 31) // 2.583
ratio=(12, 29) // 2.417
ratio=(15, 35) // 2.333
ratio=(8, 18) // 2.250
ratio=(12, 26) // 2.167
ratio=(12, 25) // 2.083
ratio=(8, 16) // 2.000
Then just save the file and close it. This feels much more natural to the car and gives the car a top speed around 170mph. That's on Riverside, the longest straight I have. Changing this file changes all the cars since they all use the same driveline setup. You also have the ability to copy paste in the same setup from other cars BUT you need to also change the HDC file and match the "Gear1-6Setting" otherwise you'll end up with stacked gears. Speed safely!
