Its not a FM engine. Its a mix of a sampleplayer and a subtractive synth.
You cannot use the filters on samples. But you can use the filter on the square- and the sawwave. So there it will make an addition to your QS6.1, because you should be able to make filtersweeps. I cannot remember how controllers are implemented and thats why I'm not sure of the sweeps.
I also think that its able to do keysplitting
so you could also use it as a controller.
Anyway go to http://www3.bc.sympatico.ca/epsilon/lapage.htm and get some more info