Ford Reman 6.0 turbo issues

[TurboMustang370]

While my truck (2006 6.0) was getting EGR delete and head studs done, the shop decided to have Ford replace the turbo under warranty. A Ford dealership put on a "reman" turbo which has been leaking oil since day one.

I'd like to throw an aftermarket turbo and some sticks on the truck but I can't justify the $4400 price tag.

Would you be able to rebuild the stock turbo with a little "extra" and still run the stock injectors without risk of issues? Do your rebuilt/reman turbos carry a warranty?
Thank you!