Either amp configuration is going to draw about the same amount of current, so your electrical system will be fine as is. Some more stuff to consider...
2 amp configuration -
Drawbacks: you'll need a distribution block to split up the wiring and in some cases two amps take up more room then a single 4 channel once you calculate the wiring for each. Also you might need to buy an external crossover to split the signal between the two amps. You have to buy two amps so it might be more expensive.
Advantages: you can upgrade one amp at a time and get alot of power cheaply with a mono block Class D amps that has built in low pass crossovers and remote bass level controls. Such mono blocks can drive lower ohm loads so your good for multiple voice coils, or multiple subs.
4 Channel amp -
Advantages: one compact space saving unit, easy to wire, almost always includes a built in 2-way crossover. Cheaper then two amps + a separate crossover.
Disadvantages: not as powerful for the sub and limited to a 4 ohm load bridged. Upgrade path is not as flexible, but can still be done. You need to find room to mount one large unit instead of two smaller ones.
Bottom line: for simple systems I normally recommend 4 channel amps, its one unit that is perfect for driving a set of components up front (@ 50-100 watts) and single sub in the back (@ 200-400 watts). I've found this power level and ratio gives balanced output but still gets plenty loud with good bass response due to cabin gain.
The $30 adapter the Honda guys recommend is most likely the best way to go as then you can buy any amp combo you desire. Just make sure whatever route you take you've get a hi-pass and low-pass crossover in the signal somewhere, either in the amp(s) themselves or with an external unit like this: http://www.sonicelectronix.com/item_...2+-03KX2-.html
cub - I heard ya on Hoffman's Iron Law, I normally just simplify it to bigger box = deeper bass, smaller box = louder as I'm assuming the same amp. Now to gain those 1 or 2 dBs with the smaller box you lose the low frequency extension, so most people chasing those last few dBs will just go ported since its more efficient.
Today's subs just have huge xmax numbers in comparison to what we ran back in the 80s/90s, thermal power handling has gone thru the roof, no way a 10" could take 800 watts back then, with its paper cone, foam surround and weak basket. Honestly I'm shocked at what modern day subs can do in regards to box size and power handling, 1,000 watts subs in .4 cubes? Bonkers! Same goes for amps, you can buy a 1,000 watt mono block for chump change, often the same price as a good head unit. I remember when a dollar per watt was considered a good deal thus dropping $300-800 on a single amp was the norm.