Well, you will need 2000 watts RMS to power both of those L7s. Anything less will not give those speakers the support they need.
If you wire it up right, you could use the 2000... but it would be safer for the amp if you ran the 2600 (less chance of overheating, better response)
Also with that kind of power you absolutely will need a capacitor, otherwise you will fry your batter and potentially your alternator too.
Don't forget he massive box that you will need; both of those speakers in the same box would need 5-6 cubic feet of space total