OK so what if I brought a Chinese k04-015. And a new compressor wheel could I take the hot side from my turbo (k03-029 I think) along with all the insides (maybe a rebuild kit) and the cold side from the Chinese turbo along with a better compressor wheel would this work as a hybrid?
If it's working fine, keep it as a backup for when the chinese/hybrid fails. Do you have supporting mods? because a larger turbo will be restricted by the exhaust, single SMIC, small (?) injectors, tune. I'd start with those.
Did you upgrade everything I've listed, except the injectors?
I would NOT pick up a Chinese turbo, not even for the housing. Even if it's machined to be exactly like the KKK ones (and could fit your core), I seriously doubt the material is the same as the KKK ones'.