i run high boost on mine coz while rebuilding the lump i brought some low comp pistons and a grs,when the tuner increased my boost to 21psi on mine it ran lean top end, hence why i had the fuel pressure mod to correct it,

taking to to a tuner who tunes from road test info is a very good idea i had mine done this way.

one thing a liked about my fuel pressure mod is that i know i have the fuel, and didnt really like trusting a old ford cold start valve and more wiring to the control unit, i would save an extra 150 quid up and get a MF2 one with a proper cossie injector in your charge carrier, but its just advice on saving your engine...

also what intercooler do u have?, a pace will be on its limit at 18 psi, grs, pro alloy etc u have no problems.