Upsizing from 650cc HP to 800cc UHP hopefully. From your experience will I see much of a difference? (Photo)

Before exchanging to a larger implant, do your homework. Your tissues are already stretched with the 650cc implants that you have, going even larger could cause permanent damage to your tissues. Short term satisfaction may not be worth the long term effects to your breasts.

Yes, you will likely see a significant difference; of course, whether this difference will be a significant enough cannot be determined without clear communication of your goals.  Best wishes.