The Legacy is a little sportier than the Outback, but not in the same class as the Mazda6.
The Fusion feels too large and heavy, but is also quiet.
Really, though, even the Mazda6 doesn't feel all that sporty. You need to step down a size class for that.
Is a hatchback out of the question? If not, the new VW Golf is worth a look. Interior space isn't far off a mid-size, but with the handling of a compact, and quieter inside than a Mazda3. Reliability has been good so far--though it's early. With recent VWs reliability has tended to be good for at least the first 4-6 years. Beyond six is the big question mark.
Aside from noise levels similar to the Mazda6's, the Mazda3 is an excellent option. If the car is fun enough to drive, maybe you'll find a little extra noise doesn't bother you so much?
If you are going to get a manual transmission, the Ford Focus is also a contender. Its rear seat is less roomy than the VW's, but it's quieter than the Mazda and I think the VW as well. Good handling with the SE Sport Package. Plus it's often possible to get a great deal on them. I wouldn't suggest the automatic because I'm unsure of the long-term reliability of the transmission.
The Buick Verano is quieter than any of the above, and handles well, but has numb steering and a rear seat at least as tight as that in the Focus. Reliability has been good.
If you drive any of these compacts, even the Mazda6 will feel boring in comparison.
The Chevrolet Sonic suggested above is two size classes down. Not much power. But it's by far the cheapest car you can buy with forward collision warning, a great safety feature, especially for young drivers. This feature is also available on the Buick and Mazda, though only on the latter when fully loaded and without a manual transmission.