Mental Addiction and HiBoost are both currently working on Turbo kits for the 2.3L (and with HiBoost, 2.0L) Mazda 3 vehicles.
They should run you around $3000-$4500 depending on what happens by the time they are done.
We aren't sure yet how much HP/TQ the car's transmission can handle though, or how much boost the stock internals. Is your friend's pricing including a complete engine and tranny build up as well?