If you wire in in a parallel circuit, yes, it could overload the receiver by causing it to go into thermal protection.
Who knows what load it is really intended to receive. I suppose you could try that, but you will likely end up with a really bizarre response. The subwoofer output on that receiver might be EQ'd for that crappy bandpass woofer that the unit came with, and no way to change it. I wouldn't be surprised if it was bandpass filtered between 40Hz and 120Hz.