Im 5'8" and 160lbs and currently a b cup. Is 525cc implants to big or will it give me a nice d cup?

Choosing the right implant to meet your goals can be a tough decision. I wouldn't get too caught up with an exact "cc" to reach a desired cup size, because the implant size required will depend on your specific anatomy. This includes the width/height of your chest wall (rib cage), and the position of your breasts. A good surgeon should be able to look at your chest, and identify the range of implants that would achieve your desired shape and size. In my practice, patients bring photos to their pre-op appointment that demonstrate the size and proportion of the breasts they desire. This eliminates the ambiguity of cup size since a Victoria's Secret D-cup is different than a Calvin Klein or Nordstrom D-cup bra. In the operating room, I use temporary sizing implants to match your breasts to the pictures you have picked, and can then select the exact implant needed from a large consignment I keep in the OR. This has been an excellent method to match a patient's desired size, and foregoes the need of selecting your specific implant prior to surgery.

It sounds too large to me.  It will have the effect of making you appear heavy.  Stick with something in the high 300, lo 400 cc range.

Unfortunately, you have not told us your bra size just your
cup size. If you are 32 or 34 each 100
cc’s of implant corresponds to 1 cup size change. If you are 36 or 38 each 200 cc’s of implant
corresponds to 1 cup size change. From
this, you can compute the volume required to achieve your desired goal. I always recommend small round textured
silicone gel implants placed retro-pectoral since they look and feel more
natural, are more stable, less likely to ripple or have complications needing
revision. Implant profile is irrelevant
in the retro-pectoral position since the muscle compresses it. Best Wishes,Gary Horndeski, M.D.