Breast augmentation. Is the difference between Sientra high profile 330cc and 350cc noticeable? 105-107 lbs, 5'3"

20cc is the exact volume of one tablespoon plus one teaspoon (or 4 teaspoons). Put this volume in a glass and try to imagine this amount over an entire breast making a difference. It would be like asking if 5 potato chips more or less would make a visible difference in a whole bag of chips. Even in the cheapo small size, you probably couldn't tell the difference; with the regular size and especially with the big bag, there would be no way to see this small difference.
The same thing is true here. Over a whole breast, 330 vs. 350 is an invisible difference. That is why implant companies manufacture implants in 30cc or larger increments--this is well BELOW the threshold of visibility!
I think with your size and weight, implants in this size (either one) will add about a cup and a half to your present size. You might expect a B to C cup result, depending on where you buy your bras. This will yield a nice, natural, and still sleek, feminine look, IMHO. Best wishes! Dr. Tholen

No. A 20cc difference is not a large amount. For your reference, 1 tablespoon is 15cc so both implants should look similar. I would not expect a noticeable difference. Congratulations on your upcoming surgery.