Can anyone show me what a 650cc, moderate plus, under muscle would look like?

In my practice, I use Crisalix 3D simulation with which you can see what size of
implant would suit you and how you would look post the surgery. So depending
upon whether you choose 280 cc, 350 cc, 650 cc or whatever size you choose, you
can see how it would look on your body. I would recommend you go for 3D
simulation; patients really appreciate that.

Everyone looks different after surgery. You will never have two patients alike. What I can suggest you do is go through a few different surgeons before and after photos and find a patient who has a similar build as you and has gotten implants that are about the same size as what you are wanting to get. That will give you the best idea for what to expect after surgery. Congrats and I wish you the best of luck!

After I discuss with my patients their goals, I measure them and then look at pictures of women with similar measurements with different size implants. My patients tell me that this process gives them a good idea of what can be achieved. Ask your surgeon to show you.Dr. Ted Eisenberg, Board Certified Plastic Surgeon and Author

There are different computer simulating programs to assess the best breast size when you sent your pictures. However none of these programs are better than a experienced surgeon's eyes. First of all how do you know that you need a huge implant? Do you have breast ptosis (dropping)? What are the exact sizes of your breasts? Big breast does not mean a beautiful breast. A beautiful breast should be in harmony with your torso and should have a good conical projection with upper fullness and correct nipple position. So it is better to leave the decision about your breasts to your board certified plastic reconstructive and aesthetic surgeon. Good luck.

Keep in mind that the use of 650cc breast implants  may achieve a very different "look" for one patient, compared to another.My best advice: more communication.
It is definitely worth spending more time (prior to the date of surgery) with your plastic surgeon to discuss further.  As you know, it will be important for many reasons, that you feel comfortable that you and your plastic surgeon are on the "same page" prior to proceeding.
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, in bra sizers, and computer imaging) as well as careful measurements (dimensional planning) will be critical.
Generally speaking, the best online advice I can give to ladies who are considering 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. For example, I have found that the use of words such as “natural” or "D or DD cup” etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup size may also be inaccurate. Again, the use of computer imaging has been very helpful during the communication process, in our practice.
3. Once you feel you have communicated your goals clearly, allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals. Again, in my practice, this decision is usually made during surgery, after the use of temporary intraoperative sizers.
I hope this helps. Best wishes for an outcome that you will be very pleased with.