"Used cultured bioware", no. You can't have something specifically tailored for your genetics, that you got 2nd hand from somebody else.
However, CF pg 70 says "omega cyberware is often first-generation, just cheaply made and a knockoff of more popular ’ware." So it's possible you got your implant from the same store that sells Okelees and Raibam sunglasses too. The sidebar on CF pg 71 talks about omega-grade having drawbacks. The book suggests drawbacks like not giving the full bonus, or little quirks in operation. But that's for Cyberware, plus it sounds boring.
For bioware, I'd probably lean towards things like negative qualities. Like a mild allergic reaction to the implant, permanently saddling you with a -2 to everything you do. Or maybe a Weak Immune System. Maybe there's something you can take for it, but the prescription is rather hard to come by, and the only people who take that medicine are people like you. So even asking about getting some, tells people what you've got in your innards. "Hey man, you know where I can score some El Cheapo?"
Or maybe the "implant" is really an organ harvested from a Changeling or something. Little does anyone realize, their unique genetics make them universal donors. But it also means your ordinarily mundane aura is going to have a very bright spot just above the kidney. Plus, someone is eventually going to come looking for their bits and pieces back.