"On a diesel engine the turbo is on there to just keep EGT and emissions in check."
This is the first time I have ever seen a statement like this. Turbos have been used on diesels since forever to boost HP - John Deere tractors, semi's, etc. Long before there were any emissions standards at all.
In fact, possibly the coolest diesel car in existance - the Audi R18 Le Mans racer, gets approx 500 HP from a 3.7L turbo V-6. I doubt that the turbo is on there for emissions reasons.
I'm really not trying to be argumentative as I assume there's a little more to your statement. I'd really like to know what you mean.
Tim