2005 F350 New Turbo

If you're not upgrading to a tuner right now, look at the Wicked Wheel 2, there's a couple of guys on the org who like them and they're pretty reasonable.

Myself, I'd save the money and use it to get away from that 6.0. But if that's not your plan, these guys really know their stuff.
ATS Diesel Performance

What are your goals? Unless you want significant more power why not stay with the stock?

The Powermax in the link above is a well regarded version of the stock turbo, but having a larger impeller it needs to be run with a tune. So you have to add the cost of the tuner and the software to the cost of the turbo. Then you get into the whole head stud thing. I wanted to remain stock, but to try an aftermarket turbo since the truck has had two Garrets. If you don't drive them the variable vane system tends to rust up and stick, and I left mine parked outside all winter, didn't even use one tank of fuel, so it was my own fault. You have to drive these things regularly...

Brian

I'm a fan of the bulletproof guys, and here's what they have. A bit more $ tho. Their customer service is great as well.

I just installed a Rotomaster, bought from Diesel Power Products. Brand new so no core to return, made in Canada from all new parts, nothing is rebuilt. Completely stock compatible, but some detail changes to the impellers and vanes give it a bit more flow. It was $995. Best value I could find, and it came with the install kit (o-rings for the discharge tube, gasket for the oil supply tube and new bolts). Took about four hours to change, but I'd never done one before. Very happy with it.

http://www.dieselpowerproducts.com/p-11365-rotomaster-new-upgraded-vnt-turbo-04-07-60l-ford-powerstroke.aspx

Brian