Here we go again, i've read all I could on the matter and here are my questions:

If I fit the 255HP into a phase 1.5 (98 JDM Forester), can I detect if the regulator is not up to the task by fitting a fuel pressure gauge? If the standard reg is not up to bleeding off the high fuel flow, and this results in higher flow through the injectors, would this not show up on a fuel pressure gauge as an increase in pressure over the standard 43.4psi (which is the figure I read in the ws manual)?
My car is.. quite standard, and I have no intention of doing a remapping via PowerFC etc. If my fuel consumption has gone up, can I remedy this with an adjustable regulator, and how would I know what to adjust it to? Set a new pressure based on wideband AFR readings?
Or should I just shut my ^&@$ and get rid of the 255HP and install a 190 model?
I recently installed the 255HP in a pinch when my standard pump died, and was assured it would be a drop in and not cause overfuelling, I have not put much miles on the car since then, it drives perfectly, but it SEEMS to be consuming fuel faster, I got about 60km off the first quarter tank with city driving and just a tiny bit of 12psi booting. Im accustomed to about 75-80km from that same behaviour. So its bad to worse...