Welleman K4005 Amp

I'm thinking of using it as a monoblock, http://www.velleman.be/kits/k4005.htm

But. I'm a little confused about the power ratings and impedance.
The powerrating is very critical. If you bridge this stereoamp into mono, you get 200 watt and then you need +/- 30-35 volt, impedance can't go under 8ohm.

But if I want to drive 2Ohm load, can I just put a large resistor in series with the output?

My second question is; Can I drive them with less voltage then specified? Like +- 20 Volts

Any answers are very welcome!

Best Regards, Christian