Use this:
Car Lease Calculator — Monthly Lease Payments and Costs
to determine if it is a good deal. At first glance it appears it is not. Residual on the 370z (from my dealer is 56% with 15k miles per year and 57% with 12k miles per year) Also the money factor is .00325 or 7.8%. Is he selling the car to you for $31,000 less you cap reduction or is the 31,000 including the 2500 cap reduction? That will make a difference in the estimated lease price as well. Hope this info helps.