One hundred cc's difference is 3 1/3 shot glasses or about half a cup size (differs from patient to patient). The amount of native breast tissue and the thickness of your fat layer, whether you have rippling presently are all important factors. If you want to stay with saline implant I would recommend considering the IDEAL implant which is the newest technology saline implant made to feel similar to a silicone implant. The Ideal Implant®, a new breast implant FDA approved and now available to the public, promises to change all of this. The Ideal Breast Implant is a saline implant with the natural feel of a silicone implant made possible by its innovative double-lumen design. This design consists of a series of nested shells which control the flow of liquid inside the implants, giving them a more realistic feel than standard saline implants.The Ideal Implant has completed its two-year trials with stunning results. Of the 472 women who came in for two-year follow-up examinations, patient satisfaction for those who received the Ideal Implant as their first implants was 94.3%. Satisfaction among women who received Ideal Implants as replacements for their previous ones was 92.3%. Surgeon satisfaction with the results was also high (96.5% for primary implants and 93.4% for replacements).See the below link for more information. Regarding size: It is very difficult to determine the exact size and shape implant you will require to best match your ideal breast image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your breast will determine, in many cases, the maximal volume per implant profile that you can accommodate. To illustrate; a 100 cc difference may make a significant difference with a narrow base width breast, but much less of a difference if you have a wide chest wall and wide breast “foot print”. Therefore, just because your friend may have a great result with let’s say a 350 cc implant to make her go from a “A” cup to a “C” cup size does not mean that you will have the same result with the same size implant. . Further simply placing implants in a bra to determine the size best for you is not always accurate as the bra often distorts the size, is dependent on the pressure the bra places plus the implant is outside your breast and not under it among other variables. Computer software morphing programs that automatically determine the best implant size can be helpful in some but not all cases (e.g. doesn’t work well in my experience with existing implants, sagging or asymmetric breasts). Using “want to be” photos however are useful if simply provided to the surgeon.