Check out comparables on Autotrader.ca. You'll have to check the warranty coverage, and it has nothing to do with the lease. At coming on three years old, 80K is not "high" mileage. At 25K per year, that's 75.
However, $60K for ANY used car other than a specialized AMG, M, or Porsche, you're still asking to ride a big depreciation fall, but if you love the LS430, it's still a big savings over a new one.
Don't forget a PPI, even if it's under warranty, to be safe and make sure you don't get a crash repair.