I have to comment on the "understeer" issue.
In my experience with RWD performance cars, 9 times out of 10 any understeer has more to do with driving style than the actual car. An extreme example was at an autocross a year or so ago. I was talking to a relative novice in C-Stock, and he was complaining about his Miata understeering. He asked if I had swaybars, shocks, etc. to get rid of the understeer. I explained that I didn't have any understeer problem to solve. He was having a lot of trouble, so I went on a ride with him. He was going in so incredibly hot that he was locking up his front tires under braking and then wildly swinging the steering wheel as he entered a sharp 180 degree turn.

Of course the result was that he was plowing right through the outside of the turn.
I took him on a ride in my car (which is more stock than his) the next time out, and the light bulb went off. There's no understeer if you come in slow, hit your (late)apex, and squeeze onto the throttle as you unwind. It's much faster too.
"Go slow in the slow parts and fast in the fast parts".
The point is, understeer and oversteer are dynamic - they're not the same in all conditions. For optimal handling, you really want a car that is setup to slightly understeer. This allows you to adjust the car's attitude with the throttle. I can't seem to locate it right now, but there's a book called (I think) "Secrets of Solo II Racing" that has the best discussion of it I've ever read.
In short, unless you've driven the Elise
and you have extensive track/autocross experience to go with the high performance driving classes you've taken, don't worry about any "understeer" you might have read about. I have a feeling the Lotus engineers probably did a pretty decent job of setting up the car right out of the box. After you've done a few events, you'll be far better able to judge how to setup the car to your driving style. Either that, or you'll realize (after losing to the hot driver in a Hyundai Elantra) that you've got plenty of learning to do on the car as-is. Heck, I've been autocrossing and doing track days for years and I'm still learning tons from a stock Miata!