It wouldn't put any more stress on the amp than it would if you were trying to output the full potential of any other amp.

The amp can only output 1kw, you could have those two subs connected to it or one single sub rated for 5,000wrms and it wouldn't matter the stress (given the same 1 ohm load) would be the same.

Amplifier's do not care what the ratings (except for ohm load) are of anything that's connected to them, they're going to output the power the input signal, gain setting and load (ohm load, resistance) basically tells them to.

If you have the gain set to where a 1.5v input signal produces maximum output then the amp will output it's maximum level at whatever ohm load is connected to it. So for the Sundown 1k that would be 300wrms @ 4 ohms, 600wrms @ 2 ohms and 1kw @ 1 ohm. The only stress that would change would be the resistance of the load connected to it. No matter what amp you're using the lower the ohm load the more stress it puts on the amp, that's it. Whether the speaker you connect to it is rated for 10 watts or 10,000 the stress would be the same on the amp at the same load (4, 2 or 1 ohms respectively).

I also put absolutely NO faith in clamp tests, they're worthless. They tell you nothing useful and show only numbers that are attained in that particular setting. As soon as you change one single variable of the thousands that are involved the entire test is void and invalid.

ill probly wind up going with the SQ 1200, 1. because it matches :D and 2. I can have a long warrenty, with the used sundown its only a 30 day money back :/

to who may care, I did go with the SQ q1200, 1. because it matches. 2. because its new.