I would really look for new car if you can. Used market isn't much lower than brand new on these cars.
you can buy a brand new BRZ limited in manual for under $26,000 with 1% interest. You will only be paying about a total of $600 in a 60 month period with $5000 down. Used vehicle will have much higher interest rate. Not to mention New 2013 model BRZ's are going for 0% interest. I would really take advantage of that, anything under 2% is a good deal.
check here and plug in your numbers.
http://www.edmunds.com/calculators/
Problem with scion is that they have Pure Pricing, which is pretty much means buy the car for MSRP. There are few dealers that will lower the price. but it won't be as much as a Subaru.