MM6501 or MM651?

I have an access cab and have done everything to my sound system except fix the "fill" sound. The speakers in the headliner are a waste, but not having the cab filled bothers me. I already have Db6501 in the front, I love them but if I am going to add more 2 more speakers I want to get even better ones.

My issue is that I would love another set of component speakers, but the tweeters are the big issue; I'm not sure where to mount them. Maybe remove the headliner speakers and mount the speakers in the access doors, then install the tweeters where the old headliner speakers use to be? Another choice I was thinking is getting the MM651 speakers, they have the tweeter already built in; I could install those in the front doors and keep the DB's tweeters in the door while moving the DB's to the rear doors since they are just for fill.