So common finance sense dictates that you even out the payments but only pay 300. Suppose that you had two options for your Porsche
Option A-pay $1150 a month for two years, total cost = $27,600
Option B-pay for 2 years, year 1 payments of $300, and year 2 payments of $2,000. Total cost = $27,600
Under Option A you would pay $1150 every month.
Under Option B you could take $1150, but pay $300 every month, and put $850 in the bank to pay as part of your $2000 next year. Using this option you would generate an extra $276.00 if you can earn 5% interest in the bank. So now which option would you prefer