Will M+K Volkswoofer Sub work in my system?

  Thanks,I spliced the speaker wires from the amp to the sub mains like you said only and it works.I was concerned about ohm problems with the amp.I had to redo the cone foam on the sub 12 inch woofer recently and now it works perfect.A hairy job as it was the first time I did it but saved the driver for about 20 bucks from kit by Simply Speakers.The M+K satellites are good sounding but just too fatiguing at high volume.

The earliest ones lacked low level (rca) later like one I had offer both.  Simply connect to the high level (speaker input). Both options are perfectly safe. First try splicing left and right mains to the subs inputs. Depending on the amplifier you may not have to create a loop. That was the case with a Polk sub I had. With M&K I simply ran signal from the bi-wire posts on the back of my power amp to the sub inputs. One channel left sub one channel right.    

If your volks has both input options try both. Depending on preamp output voltage you should find you prefer one over the other. 

If the volks is dialed in well it will enhance not degrade your paradigms.

What an old but great sounding sub they can hold there own against modern subs of today as long as the surrounds are in order.  

Man, those are old speakers! :) 

Nothing wrong with that, but probably not how you want to do your crossover.  Go from your Preamp Outputs directly to the sub instead. Unfortunately you won't have any high pass filtering.  You may want to consider a miniDSP as well to equalize and help integrate the subwoofer.