Hydrofoils for Outboard Engines: Potential Risks & Benefits

Question
I have heard that hydrofoils (like the Stingray) can cause stress and damage to lower units. Is this true? I was considering one because I have a small boat with a rather large outboard (boat IS designed for outboard). I have huge bow rise when starting from still and little porpousing issue. If they do not cause damage, are they worth the expense? If so, what is a good one to purchase?
Thanks,
Sean

Answer
SOME MANUFACTURERS VOID THE WARRANTY ON USING HYDROFOILS. DRILLING INTO THE FLANGE CAN WEAKEN THE DRIVES PLUS THE EXTRA PRESSURE CREATED BY THE FOIL.IN 20 YEARS I HAVE NOT SEEN ANY DAMAGE CREATED BY THE FOILS. PEOPLE THAT HAVE THEM, LIKE THEM. GOOD LUCK