Thanks for all your replies guys, plenty of great suggestions!
After talking to some people and looking at availability of used N300 I'm more inclined to buy a street bike and take it to track.
I just feel more comfortable with a bike that has probably not been crashed hard and it's easier for me to recognize possible damages.
@Owen for sure I'll post it in here
If you take a street bike to the track, it will cost you more in the long run repairing all the stuff you break. It will happened sooner or later
If Jacobs bike is in your budget, it's a safe buy even though it's been down (all track/race bikes have). Steve's bike is also a good buy if your budget is a bit more restricted.
Do you already have a street bike? Or are you looking for something to do a bit of everything?