Just fast road work, no track days!
I had an Elise before the Z, meaning I've been spoilt in terms of how cars handle :-) Still love my Z after 5 years though, but I'd just like it to handle the twisty stuff with a bit more aplomb!
Brakes are already a bit up on OEM with EBC grooved and dimpled discs and RedStuff pads. I've got the Brembros so stopping is already pretty decent.
The endlinks are a must, like I said, it's embarrassing at the moment! The S-tune sounds interesting, guess it depends what it's done and what you're looking for...