M45 is off a Mini isn't it? Whats an M62 come on, and can you get them cheap enough?

Thats why I was thinking roots type, purley for the low end. Pipe work wise, I can't see it being too bad, turbo compressor to charger' inlet, charger' to intercooler, intercooler to throttle body. Would be a lot simpler using a twin pass intercooler so the pipes are both on the inlet side of the engine.