I'm trying to think of things that wouldn't ruin the character of the car or add weight or too many $. Things I would change:
Some kind of skidplate by the front spoiler. My car has only made contact one time with asphalt and it did a lot of damage. I know there is some sort of plastic cover, but it's not substantial enough. If you can't come up with any kind of protection without adding weight, then maybe you could make the front spoiler a separate piece so it could be unbolted and replaced after it gets damaged.
How about a bumper made out of something more could take a small tap without costing 1000+ dollars to fix. It doesn't have to be anything fancy, just some kind of bolt on piece made out of flexable plastic.
We have very hot and humid weather in many parts of the US and on days where it is 90-100 degrees fahrenheit, the Elise can not be driven. My car has cold a/c, but it can't keep up because the chassis gets too hot. Maybe the coolant hoses that run through the car could be better insulated. I also noticed that there is almost no difference in airflow between fan position one or three. I think the blower motor is powerful but it just can't move enough air. Maybe the elise needs bigger vents for more airflow, but using the Elise in july or august is almost completely out of the question because the heat makes driving unbearable.