I think your only impedance wiring options, assuming the cab is loaded with 8 ohm drivers are;
48 ohms Series, 12 ohms S+P, 5.3 ohms P+S, or 1.3 ohms Parallel.
Your cab shouldn't have resistors in it, if it does I would get them out.
Although the measurements are in ohms for both fixed resistors and loudspeakers, resistance and impedance aren't the same exact concept, and fixed resistors really won't help you in your quest to change your cabs impedance.
This topic has just been discussed in previous threads, try a search. If you find a dead link let myself or one of the other mods know and we can fix it for you.