I think someone tried to tell you that the sbp 15x6 you have are not oem, cause Mopar never made a 15x6 sbp wheel. (My oem 15x6 lbp are 4"bs). So, we don't know the backspace of the wheel that you have for the front, and it's important.
Frankly, I would mount 215/60x15s on your sixes, and 255s...