Closest you could get, is either .8 ohms, or 1.14 ohms.
You'd achieve .8 ohms, by wiring one sub parallel, the next one series. Then wire these two together in paralell. Your impedance is then 1.6. (Figure 2 ohms and 8 ohms in paralell.. 2x8 = 16. 2+8= 10. 16/10 = 1.6) Do the same with the next pair. Then wire them together in paralell. (1.6 x 1.6 = 2.56. 1.6+1.6 = 3.2 2.56 / 3.2 = .8 ohms final)
To get the other resistance. You'd need to first get your 1.6 ohms from the first pair, then with the second pair, wire each sub series, for an 8 ohm impedance, then wire them together paralell, for a 4 ohm impedance. Then, take those, and wire them paralell with the first pair. This would = ( 1.6 x 4 = 6.4 1.6 + 4 = 5.6. 6.4 / 5.6 = 1.14 ohms)
That's the closest you're going to come to a 1 ohm impedance. Neither of these are really recomended, though. Also, in the 2nd method, make sure you wire the SUB in series, do not wire seperate subs together in series if at all possible. instead wire the voice coils of the same sub ins eries if you must use series at all.)
no, you want to send about half or little more to the sub, do not rely on max power, most subs will never handle max for very long.... And i see those are visonik, i would put strong 1800-2000 watt amp on them