What hydrofoil should i buy??

I have a 165hp mercruiser and was told to use a hydrofoil....there are a lot to choose from, which one do you suggest??

I'm not sure if the expensive ones will give you any more benefit than the cheap ones.
But when I installed on my my old 18' SeaRay, it was just something like this:

http://cgi.ebay.com/ebaymotors/Marine-Hydrofoil-Stabilizer-Sting-Ray-NEW-Torque-Equal_W0QQcmdZViewItemQQcategoryZ26456QQihZ012QQit emZ220198833744QQrdZ1QQsspagenameZWDVW

I use a Stingray foil myself. If I had to do it all over again, I'd probably just spend the $120 or so to get some Smart Tabs.

The best on the market is Bobs Machine shop from Florida. They raise out of the water when the boat planes. So they do not effect steering at high speeds.