I don't have a Veloster but the car look is WOW.
I have a mazdaspeed 3 2008 stg3 (357WHP with GT2871R turbo) and I begin my search to replace the car in 2013.
I try to found somes info on ECU reflash system like Cobbtuning or any software like Versatuner to do the re-calibration of the VT ECU database.
(Sorry if somes grammatical mistake the french is my first language)
If you have somes information on software or reflash tool please post
Thanks a lot