If you're asking:
"If buying new speakers, is 8 ohms the only thing I have to -worry- about, safety wise?"
Then, YES, you'll be fine. Consumer-level speakers in the store will almost exclusively be 8 ohms anyway, no prob.
When folks chime in about the other things, they're just trying to explain that speakers aren't everything. Kind of like this:
Speakers = tires.
Amp = engine.
speakers can only be as good as the electronics that are backing them up. The same way that you only really worry about the quality of your tires if you can EXCEED the quality of your tires with your engine, etc.
