I think Tiffany Taylor's boobs were real when she started out (saw her in more than one outfit at a glamourcon or two, and they were pretty natural looking). Nowadays, seeing as she's visiting her late 20's, I'm sure she's experienced some natural sag, and wanted to perk them back up again. Let's face it, if your business is showing off your naked body, you don't want saggy breasts, right?
Linda Oneil's boobs are for sure enhanced. Just look at an early pic of her, and you'll see the difference. Really too bad, imho, since she was gorgeous in her natural form, and didn't need her boobs done or her lips enhanced.