I was looking at holsets home page the other night and they have a large variable vane turbo in production. It's called the hy55 I can only guess its slightly larger than hy50 wich is a big turbo. That would be nice to play with and see what differnce it might make. I don't think you could get it to spool like a small turbo but it could ad some usable range. I'm gonna make some calls and see about pricing and specs. I'll post again when I have somemore info.