This time I did search and there was no conclusive answer:

Does Delta dash maintain functionallity (including those nice user-tuner features) with the Prodrive reflashed ECU's?
I mean, the first thought that would cross my mind when seeing prodrive's programmers on their page, is that they could have locked at least part of the functionallity out of the Delta dash. Did anybody try Delta dash with prodrive staged ECU?
Vlad

Prodrive is using the ECUTek reflashing software. ECUTek makes the DeltaDash. I'd bet they work together fine. Not sure about user-tune, as its not available on all ECUTek reflashes.

DeltaDash will log just fine on your wrx regardless of who reflashes it. user tune has to be enabled by the reflasher.