My rev3 was showing exactly the same symptoms. Mapped TD06 on a link G3. A compression check revealed 50 psi less on No.3
My car is currently with Pete at Sbits having a forged engine installed.
I maybe way off here, but could you not re-use all the turbo kit parts ( downpipe, waste gate etc ) and just replace the TD06 with a bigger new turbo?
As long as the footprint, oil & water lines match up. Would this work?