All DSM and EVO injectors use the square plug. You will need to solder on new clips to use either DSM or EVO injectors. The only drop in injectors would be WRX style injectors which share the same clip. You just have to find top feed injectors instead of the side feed injectors found on the STi.
Since it seems that there is a price war here, I'll step out and let you deal w/ chino. I'm not that desperate for money.