You been watching too much Terminator :-) LOL Probably tho' these things are more than possible!

Very good question! Actually I think it's very likely. We ( humans) are on our way ( the very beging stages) to becoming at least a mix of biological and machine now. Advanced beings would be further along than us. In all likelyhood they would be something other than their original biological entities. It's unknow what type of technology that they would have, so they might be much, much further along than just machines. Some species ( if they do in fact exist) could ( in theory) be virtually anything they want.

Depends on the 'theological' viewpoints of the species. There is within our own species a 'distaste' for 'other'. While the notion of incorporating 'mechanics' appeals to some, a decent chunk places limits on that notion, some even fully recoil at the idea even on the simplest terms. Ask around about the bio-chip implant as a form of currency.;-) Its no surprise that the 'Borg' are the 'bad guys' it is that repulsion to 'inhuman' things that currently drives our species. Does this apply to all species? Or are we just neurotic and uptight? Perhaps we have yet to reach a point where we are able to face the question 'what is human, really?' and are comfortable with the 'traditional' look and feel of Human V 1.0. I think at some baser level as species may adopt a lot of mechanics to improve its physical fitness but will draw a hard line in the sand to meet some esoteric 'theological' need to identify itself as 'human' or whatever word it uses. That last 'leap' to full machine is a conversion from 'human' (again whatever word the species identifies itself with) to machine, thus any species that replaces the biologic for machine would be a machine intelligence and it would cease to be _________.