Actually the MKZ has the larger V6 in it, over your I-4. For the most part though, they are the same exact car. Truthfully I considered a MKZ before buying my Fusion, but didn't think the extra flare was worth the premium.
Wow I really started quite the debate over speeding. Although I agree with what you guys have to say about merging and stopping on the highway, probably the most dangerous thing is a distracted driver. Regardless of how fast you are going or the road conditions, the best thing a driver can do is pay attention.
I might have a lead foot from time to time, but rarely get into any fender benders. Paying attention to your surroundings, and actually using your mirrors, will do more to keep you out of trouble than disrupting the flow of traffic because you don't want to speed.
Ironically, the SYNC system has done more to distract me than help. It's nice when it works, but when it doesn't recognize a voice command, well let's just say it's a little frustrating. LOL.
I just purchased a new 2012 Fusion SEL I4; thus far we love it.
We had a 2010 Fusion SE I4 and a 2009 Ford Flex SEL 2wd; traded them in for 1 car (came out ahead) even though the Fusion had 73,000 miles on it and the Flex has 51,000 miles on it.
Both of our previous cars had Sync too, so I know how it works. It's not for things like vehicle reports or anything. It connects to your phone and/or music player, and allows you to control them via voice commands. Nothing more, nothing less. Otherwise I find the I4 good enough for power, even though the V6 is great; just not for us.
I added a swirl-flow throttle plate and a K&N cold air system to my I-4 Fusion. It has ample power (hardly distinguishable from our V-6) and gets 34 miles per gallon. Great car. We love it. Way better than any of our imports.
Just bought my second Fusion. 181000 miles on my first one.
I don't care how you drive, just don't cut me off.