Quote Originally Posted by HorizonXP View Post
If you want to learn the limits of your machine, take your bike.

If you want to learn the limits of a 600 SS, rent theirs.

If you want to learn the limits of yourself, take Racer5.

That's my opinion. You could spend the same money, get 4 days of riding on a CBR125, and get race experience. Usually, the limit isn't the bike, it's the rider. The skills you learn on a 125 translate easily to a larger, more track-oriented machine. Not trying to detract from Turn2, I'm sure they are excellent. But I felt Racer5 was a better use of my time and money, for what I wanted. Next season, I will likely buy a track bike (600 SS).
In one day the OP isn't going to learn the limits of anything you listed. It's even debatable if he'd learn the limits of a 125 in 4 days.