Well, here's the unfortunate truth: nobody makes aftermarket dampers for these cars yet. I've called both Koni and Bilstein, and although they have product in the pipeline, nothing has been released as of yet.
Sure, Koni Yellows for the Mazdaspeed3 will fit the rear (and that's just what I've done), but for the front struts, you are essentially SOL unless you go with OEM parts from a different model.
You said you liked how your sister's Titanium w/handling package drove. Why not just put the OEM handling package springs, shocks, and struts on your car? That option will end up being much, much cheaper than going aftermarket.
Joined the dark side.