I've had a torn WG diaphram on My 5KTQ since I bought it...finally swapped it thanks to another MG'ing. Boost cut is only a 1/3 as nasty as it was before but I'm thinking it might have to do party with a vaccum line leak somewhere else. I know I have a euro cam on the head (.272?) and maybe a chipped or ben swann modd'ed ECU (never checked). What I'm really curious about is why I have a regular WG spring with no markings in My WG...I was expecting to see one with additionall markings but this one had none...huh? then how am I boosting right up to 1.4-1.5. I assumed I was hitting Boost cut because of the diaphram...needless to say the turbo seems a lot happier now.