What subwoofers would fit in my 1999 ford expedition?

i want them in the truck and since my ford expedition has 3 rows of seats the trunk is the place i want them in but a question is what subfoowers? i already have some 2 12 inch kickers in the back but i want to upgrade any suggestions?What subwoofers would fit in my 1999 ford expedition?**** jl's go wit the 2 15" kickers cvr dont get the comps, the cvr's hit harder than the 15's and make sure u get a good amp that matches the rms and ohms with the subsWhat subwoofers would fit in my 1999 ford expedition?I have 1 12in Eclipse in a ported box with a 600 watt high current Audobahn amp. Oh my god, it does what I want it to do. So if you get quality, you don't need quanity. I took my 3rd row seat out.What subwoofers would fit in my 1999 ford expedition?an up grade would JLAudio w7's or w13's