This is also posted on the stock ECU reflash boards.
I have an early version of the Cobb stage 2 reflash on my 04 WRX with an unequal length header, uppipe, catless DP, turboXs catback, pulley, k&N short ram, and one step hotter NGK's. I plan to get a bigger turbo soon but want to start with purchasing a UTEC, obviously for the flexibility verses the off the shelf style Cobb maps. My question is if I will be able to piggyback the UTEC to my Cobb staged 2 ECM using the stage 2 as my base with and without the stock turbo? What are my options?

Thanks

Yes. I did exactly that for a few months. I sold my AP and went with Enginuity and UTEC with way more flexibility. The advantage of AP is you don't have to mess with your original ECU tables, which can be a bit confusing, in terms of things like Speed Limiter, Fuel Cut, and OBD code disabling. These thing AP will do behind the scene, while you must know what you are doing with any of the ECU reflash systems (like Enginuity).

I use UTEC to change maps between different seasons, I have an AX map, water injection maps, ect. I do have a td06 18g turbo, Stage 2 CoolingMist, etc.... Works extremely well.