Since no one has a simple, effective and easy to replicate VNT controller I'd like to get a sooner spool up somehow. Ball bearing turbos are a option but they cost big money. Anyone?

Hi there,
What is the deal with vnt controls? I thought the vanes were kept shut until boost built up and then they gradually opened, which sounds pretty simple. Am I wrong? I've been considering putting a vnt turbo on the 240D in place of my t-3, but I have no experiance with them. I'm a machinist and I'm pretty good at creating things, so if you could dispell my ignorance a bit, we might be able to make something work.
Thanks,
Chris