Putting a full-range coax in the front doors is somewhat of a waste. The OE signal is not full-range (assuming you have the Alpine system?).
You can easily make your own 6.5 --> 6x9 adaptor plates with cheap cutting boards, or thin MDF. I prefer not to use wood due to moisture in doors. Or, you can buy them. You can buy the speaker harness, or use splices/taps (w/o cutting the OE plug).
I have this pack, and have been using them throughout my new Ram (same crappy Alpine system as my Jeep):
50 Pack Quick Wire Splices
They work perfect.