well, if you want to match your speakers impedance you could bung an audio transformer between your amp and your speakers.
http://www.electronics-tutorials.com/basics/audio-transformers.htm
It's going to effect your sound quality, though I am not sure how badly. The other bonus, though, is that it will provide full DC protection to your speakers because they will be DC isolated, your amp will be driving the primary transformer winding, not the speakers. The secondary transformer winding can step down the voltage one half, effectively doubling your speaker impedance.
It's worth noting that this sort of thing is normally done as part of a tuned speaker enclosure, I would have thought.... But hang on, are you sure it's 8-16 ohms recommended load for that amp? sounds a bit high to me.