[Fr. Frank]

The overall drag to achieve a given effect will be about the same regardless of where you create that drag - at the lower unit with a hydrofoil stabilizer or at the transom with trim tabs. The difference is in effective thrust based upon the angle of that thrust to the direction of travel. the closer to parallel to your intended direction of travel the more effective thrust.

This is why outboards and sterndrives with power-adjustable trim on the drives are so much more efficient than most straight inboards. They can produce thrust very nearly parallel to travel, where an inboard is usually pushing at 8 to 15 degrees out of parallel in a downward vector.

The most efficient thrust system available is a trim adjustable surface-piercing drive, because you don't have the power loss from going through 2 90 degree directions changes and a u-joint. All you have is the u-joint.

That being said, there are 2 times you want that stern-lifting thrust at the rear of your boat: getting on plane, and keeping the bow down in rougher water.