Been busy lately with my work and all but I finally got the mods done.
-New fuel line from the tank to engine bay (AN8)
-AN8 fuel filter
-Kinugawa parallel fuel rails (AN6)
-AEM fpr

And while I was at it I decided to put 8mm Grimspeed phenolic spaces under the intake manifold, mainly to prevent heating the fuel rails (since they're massive Al blocks)

Just did a few test runs and no more pressure drop. Biggest drop I've recorded so far is about 8 kPa @WOT. I believe the FPR was the problem but can't say for sure.

-Timo

I've been busy lately but I managed to replace the fuel lines and the FPR. Total list of mods:
-AEM FPR
-AN8 fuel line from the tank to engine bay
-Kinugawa fuel rails, AN6, parallel configuration
-AN8 fuel filter

There is no more any pressure drop. Biggest change I've recorded is about 8 kPa but that's only during high transients, no FPR can keep the pressure exactly at the set value.

-Timo