275 to 350 cc - will I notice a difference?

Thank you for your question. Difficult to answer without pix, in general if you are petite and have s smaller breast width 75cc is a good upsize aof about a half a cup size. Best to discuss in person and undergo Vectra 3D imaging to simulate your post op results. 

Dear New Yorker,   Front and side view pictures would have been helpful. You did not provide your chest circumference measurement  in inches, which is critical for the correct implants size selection.         Lets assume that you are currently 34 full B cup size. Replacing the 275 cc implants with 350 cc implants will bring you to 34 C cup size. This is a noticeable change, however, in my opinion, 34 full C is more attractive , yet, still, very natural looking. To achieve that size you will need 425 cc implants. To accommodate  the larger size  implants, you will require to have capsulotomy (scar release).        Always, consult  with experienced board certified plastic surgeons who operate in accredited surgery center for your safety. Most importantly, check the before and after pictures of redo breasts augmentation, to make sure that they are numerous, consistent and attractive with nice cleavage, perky, symmetrical and natural looking.            Best of luck                         Dr Widder     

Thank you for the question.  Although it is not possible to provide you with definitive advice without an person evaluation, most patients are able to "go larger" at a second stage, once the breast tissues have expanded (after first-time breast augmentation).  Sometimes, during this revisionary surgery, adjustment of the breast implant capsules is also necessary to achieve the desired outcome.
You will find that online consultants will not be able to provide you with specific advice in regards to selection of specific breast implant size/profile.  
Ultimately, careful communication of your goals (in my practice I prefer the use of goal pictures, direct examination/communication in front of a full-length mirror, and computer imaging) will be critical. 
Generally speaking, the best online advice I can give to ladies who are considering revisionary breast augmentation surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural” or "C or D cup” or "look unprofessional" etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate.
 3. Once you feel you have communicated your goals clearly, allow your chosen plastic surgeon to work with you in determining the best plan to achieve your goals.
I hope this helps. Best wishes.