"I just sold my 09 Fusion with a 2.3. It may produce slightly more horsepower (15 to be exact) but it is also at a higher RPM. I found the 2.3 to have almost no torque until it was revved to 3000 RPM. The Fusion is also 200 lbs lighter than the 3rd Gen Taurus. If you put the Vulcan in a Fusion the weight difference alone would provide a different experience. I find the Vulcan to be adequate for the Taurus considering the weight of the car. Not to mention the 2.3 Duratec was buzzy and unrefined when pushed hard."
This is EXACTLY my experience with my '06 2.3L MT Fusion. You might as well have a cubic yard of depleted uranium strapped to the Fusion roof until the 2.3 gets to about 3400rpm and it doesn't REALLY get going until 4600rpm. The Mazda 2.3 has to have the world's strangest torque curve. The Vulcan in my '93 LX bull was a much more tractable engine, all torque, all the time. It didn't have to row the gears half as much.
Took a road trip up to Canada this weekend and had the choice between taking the 60,000mi '06 Fusion and the 150,000mi '02 'tec bull. The Fusion sat in the garage.