There should not be issuies with motherboard if you go for a 1070, the only thing is that you may have to update the bios on the motherboard to accept the 1070. That would be the same as well for the 1060 but only update the bios if the gpu doesnt work.
Ok. Thanks for the advice I'll mull it over this week.
I've never updated a bios so I'll do some reading. Is it difficult?