I`m intersted in any reply myself for my 156.
I have a problem that looks very much like fuel starvation at full throttle and high revs. I attribute this to my greatly improved air intake system. Its quite easy to detect fuel starvation problems when you are used to running an LPG tank dry from time to time - that teaches you a lot!
For those who have expressed concerns, all fuel systems on cars have a fuel regulator to ensure that fuel pressure is... well.. regulated
to a constant pressure. This pressure is not going to be the maximum pressure that the fuel pump can put out, nor is it likely to be the maximum throughput of the fuel injectors. Using a different regulator to increase fuel pressure will increase the maximum amount of fuel that can be delivered in any given time, and will also increase the speed at which it is delivered. There should be little danger of being able to increase the pressure to a point where the fuel system in general cannot take the increase (leaks, damage) as the car will run pretty badly before you reach this limit.
As long as the pressure increase is within the capability of the pump and injectors to cope in a consistant manner then theres no problem. Certainly at smaller percentage increases this will be true, although a 30% increase may go out of the possible tolerances! The other factor is the ability of the ECU to alter the injector timings to suit. If the pressure is increased by 10% then the injector needs to open for a proportionately shorter period of time to supply the correct fuel charge. If the pressure is increased too much the ECU may not be able to shorten the injection time enough to cope and will over-fuel (hence the Honda being unhappy at lower revs when the pressure was very high).
As far as choosing 30% immediately is concerned, I would suggest that pressure is increased up in 5% stages to get the best results. When the car starts to complain, back off to the previous setting and possibly a little more than that too to allow for some leeway. You don`t want to run the car at the limit of its ability on a warm day only to find that a cold day has pushed it over its ability to fuel correctly.
To those of you who guessed I am at work and bored, give yourselves an Alfa star