I do have the race version and I've been running it for over a year now. I had unplugged the N249 hose from the top of the N75 and it did boost to 21 but would that cause my idle issue?
No matter how long you've been running it, I would replace it with a working N75 standard valve. The boost system is simple, but without every component working as it should be, you'll have problems.
With the overboost code(s) a few things that Ross-Tech could be possible issues are:
Beyond that, there's something not right with the system and I don't know if it's the software, but I doubt it. Without having it in front of me, it's hard to e-diagnose as well, so check everything out in the list and use VCDS to help you out.
If the list checks out, then think about getting a spare ECU or sending yours back for a reflash, maybe have Gonzo check it out. Any tuner friendly shops in you area?
I think he wants me to send it back regardless. It shouldn't be throwing limp mode with a tune regardless. well you know what I mean.... No shops here :/
I win! I win! He reflashed it through my computer and bam-o. She runs beautifully. Big thanks to everyone, especially Mike, for trying to resolve the issue. But like Yasha had stated, it was just the tune. But its niiice.