Especially with sports cars, leasing is usually going to be more expensive than buying. When you lease, you're essentially paying for the depreciation of the car, and sports cars tend to depreciate must faster than other cars such as SUVs or sedans. Not saying it never makes sense though. If you're one of those people that gets a new car every few years, leasing can potentially make more sense. Leasing can be tricky and it's easier for dealerships to screw you because most people don't understand what all goes into calculating the payment of a lease. There are some good lease calculators on the internet -- here is one that looks pretty good. I think it even compares leasing vs buying based on your inputs...
Auto Lease Calculator at Edmunds.com
Btw I am a financial analyst, and I have leased in the past, so hopefully that gives me at least a little credibility.
good luck!