Then you can activate as many times as you want by using Freeze Free boosters option. First option will give you ONE(ONLY ONE) FREE booster when you BUY ONE for credits. The new speed limiter hack by vjvoxz allows any car to reach speeds between 500-600 Kmph(Depends on the car's acceleration upgrade.This option is tested and is very useful in R&D/Championships events because it will help you to win the car at a very low rank.(DO NOT USE IT IN ANY ONLINE RACE!!!!!!).(DO NOT ACTIVATE UNLIMITED SPEED AND SPEED LIMIT TOGETHER BECAUSE THE GAME WILL CRASH!).(Might be Possible for R&D and Championships but it's not tested yet.But it's a useless cheat for those events and I don't recommend using it.
After a reboot of the game perfect nitro cheat works fine. Once you enable this the perfect nitro doesn't work. The new AI mode makes the car drive on it's own.