I test drove both before deciding on the VW Golf R. I would say the Taurus SHO is not only better looking but just rode better and that GINORMOUS mofia trunk is awesome! It was just really roomy and comfortable inside AND u can send the ECU out to have it flashed. Pick up like 30-40 hp I think.
The Fusion is just Boring imo.
Trunk is deceivingly huge! Its odd, but its the first thing I always show people, and as soon as they see it they understand why. I've slept in mine before. As for tune, you just need a handheld and can pick up an easy reliable 50-75hp, a few simple mods and you're looking at ~450whp. Tune only high-mid 12s. But they are a limited platform if you really want to race them or do much performance work. My 2010 is nearly to 160k miles with no major mechanical issues, including original PTU, turbos, and water pump despite their reputation. Just remember forums and FB groups are the very vocal minority.