D12 pre DEF - performance upgrades?

Yes, I have googl'ed.

07 volvo vnl with the D12 pre DEF (has working EGRS)

few random questions I have been researching ...

Turbo upgrades? I know the stock turbo is the HX52... made by volvo. I have seen Holset make a turbo also, are they the same? I've read that the stock HX52 is good up to 750hp and is also used in the Dodge 5.0 cummins.

I have also read some guys swapping the HX52 with a HX55? I assume there is a ton of turbo lag associated with that...

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question #2 - Does the dealer simply offer just a quick tune? A "Performance" tune or something? Ideally I would like to have the EGR delete done (a tune would be nice just to turn it off an keep them closed) I'm not looking to spend thousands on a tune...it drives an runs fine..

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I'm sure it has been gone over three million times, Yeah I know...its a d12.. I'm not looking to win any races by any means but just curious. I was simply researching to make the truck run a little cooler and have cleaner oil and that is why I started looking an reading all of the different stories from the other drivers on the road.

anyways