Whats lambda link, lambda knock?
They should just be able to tune the boost, to be honest i wouldnt bother touching the boost if its at 15psi, vf22's like to sh!t them selfs at high boost (ive heard).
checkthe hose between wastegate and turbo and there will be a little thing with wires running into it, unplug it and put a boost tap in its place you should be able to tweak how much boost and the link wont be able to counter it, well this it what i did with my link which is only a g1 but i think it should be much the same?
Before tweaking things like this it pays to ask people who know, when i had the boost tap running 15psi it seemed so much slower than when the tune got fixed and run about the same psi
but i had my boost tinkered with, along with afew idle issues and he hada look at my gauges that werent working, all up it cost $150