hey stevo! there are no boost leaks or anything?
your problem sounds very similar to one of the guys at work who has a VL turbo. had the exact same symptoms and all, weird idle & no power under boost, the boost guage read 9psi and absolutely no extra power, it was the same as driving an NA one.
It tuned out all of the injectors were blocked up with crap & one injector was faulty. injectors were cleaned out/replaced and it ran good again.