Dude don't trip. The s2000 can be a safe car and generally is. Learn to drive it and you will be fine. I got mine when I was eighteen and was mature enough and safe enough to survive
If youre small and your head doesn't stick over the stock roll hoops then a roll bar is completely unnecessary. The stock roll hoops will be fine
My insurance is 140 a month. One small accident and zero tickets.

 

I drove a brand new IS350 as my first car. Granted it is not sports oriented, people said 300+ horses was too much for a teen. I never had a problem with it- it matter how mature and responsible you are. You shouldn't be rolling over on the streets unless you are pushing the car hard, which you shouldn't be doing on the streets, especially if you have no experience.