I will never go again without a car under 150,000 miles in the driveway. At the rate we're racking up miles, I'll be there with the current car at about the time it's payed off. It'll get bumped to second string and we'll get something else, either brand new or CPO.
On a lease car, I'd do tint (I live in Florida, so I fully understand window tint), and a wheel/tire package. As others have pointed out, you'll be on the line for tire replacement if you run the originals, so it's a wash, really. I'd leave everything else alone. I wouldn't want the lowering springs to cause the dampers to wear out before turn-in, which would be another expense. No stereo, but maybe some closeout speakers if I feel the need. Possibly one of those clear bras for the hood and bumper to keep it from getting rock chipped. Other than that, drive the wheels off of it, but don't break it.