need a new amp and maybe some speakers

i got a 10 inch kicker being pushed by a 750w mono amp. Hits pretty hard, but i want to get a 12 or a 15 to conserve some space.. i got a 97 ford explorer and shit sounds nice since its a box in a box so to speak. Also should i go 4 ohm or 2 ohm?

i was looking at JL, Rockford Fosgate, Kicker and Alpine amps..

this is the specs for the 15 and 12" kickers i will probably put in a sealed box.. or should i go ported?

12 inch kicker
* 12" subwoofer with dual 2-ohm voice coils
* square SoloKon polypropylene cone with Santoprene rubber surround
* power range: 50-600 watts RMS (300 watts per voice coil)
* peak power: 1,200 watts
* frequency response: 20-100 Hz
* sensitivity: 88.8 dB
* mounting depth: 6-3/4"
* sealed box volume: 0.88-2.0 cubic feet
* ported box volume: 1.75-3.25 cu. ft.

15 inch kicker
* Impedance: dual 4 ohm
* Power Handling: 2000 Peak watts (1000 watts RMS)
* Sensitivity: 89.4dB
* Frequency Response: 18Hz-100Hz
* Mounting Depth: 8-11/16"
* Mounting Cutout: 13-3/4"
* Recommend sealed Box Volume: 1.5 - 6.0 cu. ft.
* Recommend ported Box Volume: 3.0 - 6.0cu. ft.

speakers i have a pair of earthquakes on the front.. and the stock jbl's in the rear, im probably going to keep those all earthquake for now.

hmm havent heard them, ill check them out tho.. thanks.