Hello, I am located in Canada and would like to ask everyone a question regarding a trade in.

I financed a 2013 Mercedes C300 4matic with sports/bi-xenon package less than 3 weeks ago putting down $17,000 and monthly payment of $520 for 60 months at 0%. If you do the math, that is actually lower than the normal price of the car as I got a pretty good deal on it. The value of the car here is $48,000+tax.

The value of a 2013 STI Sedan with tech package is $43,000 + tax and the website says there is a 4.9% finance for 60 months which I think the dealer will have no problem making it 0 or close to it.

The question is..what is the approach I should be taking on this? Ask for the difference back in the downpayment? or a smaller monthly payment? I knew I should have chosen the STI to begin with (missing the manual and performance of my s2000 already).

Thanks for the help!