So you are going on the 5th? You are going to be going in a spec car vs your own? Deffinitly run the evo, don't mess with the spec car. The spec cars will handle quite a bit different. I didn't drive one but was told it was like a go cart. The evo would be cheaper, a better learning experience, and more fun.
We have only gone once and are no where near good. I slid off the track twice, James did once. We were trying to drive the car beyond our means.
You will definitly get several good pointers, there will be people there all day to help you. We will be in either 1 or 2 vipers, I can take you for a ride but get in at your own risk
I will probably be going slower just trying to keep on the track. Don't worry about going slow, there are designated passing areas so you don't have to worry about someone trying to pass or being in the way.