My friend bought an RS legacy today knowing that the turbos weren't functioning properly, but on the way home after stopping and starting the car a bit after the check engine light came on, it started to build boost (only 4 psi) and then felt like the engine cut out for a second or two, then later on it would boost 3 psi roughly, and stay on 3.
As we got near the end of the drive the check engine light came back on, and once again there was no boost.
Has anyone else heard of anything like this before? Its got us pretty stumped.