Is it stupid to pay a monthly payment of $551 for a 2007 Dodge Charger RT?

I am a recent college graduate with plenty of student loans that are deferred. I do understand that my credit is not great. This payment was offered with a $4300 down payment and an "ok" credited co-signer. I just feel that this may be too much to pay for a four year old vehicle. The vehicle is approximately $2100. I absolutely love the car and it has everything that I want. I just feel that for a 2007 the monthly payment is too high. Especially with a $4300 down payment. What do you think?