What programer or chip are you running?
Also if you'd like to save some money the Wicked Wheel II turbo wheel is a direct replacement for under couple hundred. It gives a few more PSI, eliminates turbo surge when towing, and very slight reduction in EGTs due to the design of the fin/wheel combo. It wasn't a huge difference but my truck is parked or towing and its been worth it to me so far. Also for the transmission you can do another affordable upgrade at home too.
When you remove the transmission pan for a service you can replace the valevbody with one custom made to your driving style/needs. John woods transmission and Bryan from BTS Transmission build them for your truck and specifically. Takes about 30 minutes to install and changes the shifting to your desire within reason of course. Both of those would be cheaper/easier then messing with a whole nother turbo. The only ture upgrade would be T4 kit but thats $$$$. Another option but has extreme love/hate is KCTurbo but again you're gonna get love/hate no where in the middle so I just never bothered.