Sorry if this is wrong forum... looked for like 5 minutes and decided this is best I could go with. I have the 2006 Mustang GT and I really REALLY want to do all the work myself to push the limit on the 4.6L to get max horsepower for my budget. It was suggested I just give in and do a trade in and refinance my loan with FMC. To my limited understanding it seems I could just give them my car for 16k or w/e and raise my loan up to 45k or w/e it is for the '11 GT500 right now and use that 16k for down payment and initial payements. Would I keep my same monthly payments, $420 and 0% interest or would they recheck my credit score and decide which interest/payments to go with? Anything extra you can tell me, awesome.