No, you don't. Metra makes an adapter to fit 5.25 or 6.5 woofers and up to a 1 inch tweeter in the factory 6x8 location. You might have to file or dremel it out for 6.5" woofers though.
I got mine for 8.95 on eBay. They are a bit flimsy abs plastic so I put some sound deadener on mine. Completely rattle free! Very easy to put comps in ranger doors.
I used some cheap 5.25 power bass comps I got for $37 on amazon and they sound great. I used some rtv sealant around it to close out any gaps that could cause cancellation, and mounted the crossovers in the lower door with double sided tape.
This way you can just run the factory speaker wire to the input on the crossover. No running speaker wire through your door jambs. If you want to amp them just run the speaker wire from the amp to the harness behind the head unit. Easy like Sunday morning!