Is it possible to turbo-charge an 08 Mazda 3 2.3L touring sedan?

Yes there are tested turbo kits out for the Mazda 3 and many people have them installed. Two of the major distributors of the turbo kits for Mazda 3 are Tri-Point Engineering and Hi-boost. Check out their websites for more info : )

I say that because I have an 08 Mazda 3 hatchback and am puttin a turbo on it this summer.

Zoom Zoom baby!