I understand the 970 is similar to the 1070 without amps...but other than that are there differences between the two that would lead to the 970 sounding better than the 1070 if both were connected to an external amp?

The 970 is identical to the 1070 except for the removal of the amps. The only reason it might sound better would be the elimination of the 1070's amps from the chassis - that would get rid of the higher voltages required by the amp sections. It's not going to be anything significant, though.

The $200 in savings associated with the 970 over using the 1070 as a pre-amp wouldn't have any audible difference, but it might make your wallet find it prettier sounding.

Thanks Gonk. The only thing I noticed on the 970 product page was mention of "Performance Matched Op Amps in the Critical Path". I didn't know if this was something different in the 970 which led to an audible difference.

I'm not aware of any parts selection or component choices that differ.