A few months ago, I was searching the web for information about variable vane turbines and I ran across a web site selling a kit to make Holset turbos on Cummins diesels spool faster. What they were selling was a spacer between the turbo and the manifold that would block one side of a twin scoll housing and force all of the exhaust through the other side. That would effectivly halve the A/R for faster spool up. Then it would open up and let the exhaust flow through both sides like normal. I don't know if they set it to open based on load, RPM, boost level, or all of the above. It looked a lot more durable than the traditional variable A/R turbine housing and since it wasn't part of the turbo looked like it could retrofit any twin scroll turbo. BTW, this isn't related to the actual Holset variable turbine turbos. I was going to research if such a set up could be used on a gasoline motor. My problem is that I can't find the website that sells them any more. Has anyone else seen anything like this?