VCDS should be the first thing folk buy with a VAG car.......especially when modifying it
So you're saying you've put the standard intake manifold (with no tumble flaps) and PCV system back on, and since then, it's throwing the code?
What's happening is when you crack the throttle open, it's going too lean. Normally that's caused by an air leak. What brand of RFD did you use? Some of them are crap and allow a leak across the cylinders.
I think you need to go over the recent changes and check for leaks. R Tech (or any mapper) can't fix hardware faults with software unfortunately.