Ragwheels tended to keep the same basic anatomy as their original form. Coggers found that adding extra limbs and whatnot made rejection and madness more likely - and they didn't even talk about the experiments with extra heads or the merging of multiple individuals. So most of the time ragwheels had one head, two arms, and two legs, though some mucking about with proportions was possible.
Ragwheels shared some basic biological traits with their base species, and the extent of the differences depended on which parts had been replaced or altered. That said, some things were consistently disrupted. For instance, most ragwheels did not sleep, regardless of what alterations were made -- a fact that fascinated many coggers.
Now that's not to say that a rag didn't need rest. Early ragwheels certainly tried to go completely without. Unlike normal people, they don't just fall down from exhaustion. But it became clear that even though they could, they shouldn't. At best, they would just drop dead. And I say "at best" because the ones who didn't went mad... suddenly, like their reason just shut off. Someday, when you're older, I'll tell you the story of Khnem and what he did in the temple of Mukar'ram.
Genetics and Reproduction
Most Ragwheels could reproduce with members of their base species, but the children are of course also members of that species. New Ragwheels were constructed, not born.