Stereo & Electronics - Subs into Mids

I have a 2000 t/a w/ moonsoon.
I would like to replace the stock subwoofers with a mid-range speaker, or a Component system, the speaker would be 2 ohm Infinity Reference, and i was wondering how would i get the sound there like the hatch speakers and the door speakers have (full range). What would i wire into?
Later in i plan on buying a subthump box and geting a pair of subs.
Any ideas?

Why do that?

why not? i dont want subs there, little two 6.5" subs wont put that sound two 12" subs can. So i rather have them playing the mid to high range when i replace them.

What do you use for door speakers?

i will be changing them to Infinity Reference 6010cs 6-1/2"/6-3/4" 2-way Component System, and i would like thoes inplace of the subs.

Well, if you like Infinity, then I guess you can do the sails as you mentioned if you're going Infinity all around. But if you're not very familiar with Infinity, buy them from a place with a return policy and listen to them for at least an hour straight. Many people, myself included, find them too bright.

By the way, don't be concerned about getting a 2 ohm speaker. You can go 4 ohm with no problems.