Hi,
Not to worry so much, if they dd not go up to you, shold be fine.
And 120kmhr is not really that fast yet, they are all out to caught
those really fast, like 140kmhr.
And if they never catch you red handed, even better if you are
driving your own car, as in the car is registered under your name.
It will affect your insurance in future.
Hope this helps. I got caught once before for speeding at 139kmhr.
Didnt know where they popped up from. So went to court and was
fined $650, on top of my illegal exhaus.( I was driving Nissan S14
at that time). But when I attended the court, I found out that my
speed was the lowest! The court was full of people caught for
speeding, and you wont be surprised to hear some speeding at
170kmhr or even higher.
Thats my experience.
Be more tactful when you want to speed...
cheers