Ok but this is kind of contradicting
one an amplifier lets say rated
1000 @ 1 ohm
700 @ 2 ohm
500 @ 4 ohm

obviously going lower on ohms will affect the power output to the sub, so yes it does affect the performance of the sub

And they don't just make different coils for amplifier choices, but as well amount of sub setups
And subs wired to 1 ohm will not actually sound as clear as 2 ohm, something not many know
Less resistance for the amp also means less control

 

you took the words right out of my mouth

 

I don't know of any good solid brands that produce a 5 or 7 channel amp, personaly.

and +1 on the amp/ohm/coil comments.

Remember that your power output all depends on your setup.

Buying 2 2ohm subs doesn't mean it will run at 2 ohms, likewise buying 2 4 ohm subs doesn't mean it will run at 4. When you wire subs together the resistance can half, double, or quarter. It all depends on the wire up. So take into consideration exactly what setups you can choose from with a pair of speakers, then you can shop for an amp that will power them properly.

I have seen people 10000 times buy a pair of subs, buy a cool amp, only to find out that their subs will only run at 8 ohms, which on their nice little amp supplies about 75-100 watts to each speaker which were rated at like 400 watts. Talk about a ****ty situation.