The new looms etc will certainly help with maintaining battery voltage, which will help things, did you try an extra 2psi of boost to see if the AFR started to correct? it will be on the top line of the map at 14psi, and on a stage 1 will be heavily using the WOT adders too,

You should set your fuel pressure to 3.5bar with the vac line disconnected.
The fact its up under load shows it is raising rate.

Do you have an AFR plot?

The next step would be to drag some data from the ECU to check all the sensors are operating well and calibrated ok,
If all is well, the fix is quite easy, if the AFR is good everywhere else, a simple reduction in the WOT table would probably fix the issue.