High profile silicone is good for volume enhancement with a smaller diameter implant, however, they usually do not appear natural. Some surgeons swear by them. Placement is of crucial importance. Shifting can occur as well, leading to undesirable results.
If you do not have a lot of fat, don't go too big. That's key. 400 ccs sounds aggressive for your measurements. Under the muscle is the way to go.
Hope this helps!!!
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