If this is a financial decision it really doesnt make sense. The only true financial option is to refi your 6. Any other option would cost you higher interest, depreciation on the existing car (by eating it at sale) and depreciation on the car you wish to purchase.... also factor in the fees and sales tax.
If cash flow is your primary concern then paying cash for a junker is an okay idea... as long as it doesn't break. If it breaks then you are probably worse off. (it will also eat your cash and dip into the money you are trying to save)
If cash flow is the most important thing and you dont put a lot of miles on your car then go get a really cheap lease with minimal money down. You can get a really nice car for 200 a month with a warranty and get rid of it in 3 years.
Beware of cheap older european cars such as an Audi... that will eat you alive.
