There is not much you can do to meaningfully lighten the car. The oem exhaust is pretty heavy, so you can save some weight there. I ran around with a 14 lb battery for a couple years, but ended up switching back to a regular battery due to several issues.

I would have an aluminum driveshaft made before doing anything to the interior.

Fortunately, at 3220 lbs it is a fairly light car already.