Wastegate & Wheel
In theory if you were just going to change out the wastegate, you wouldn't need to pull the turbo, but this wasn't all that we had planned for the day. I can't imagine actually working that deep and that far back on the turbo, so my take is to always pull it if you're working on it.
Getting started we changed out the compressor wheel on the turbo. The 6TP38 compressor wheel from BD Power has an extra fin and is just an overall better aftermarket design than the stock version. At first it didn't spin freely, so we gave it a little tap and that's all it took. Compared to a Duramax, the compressor wheel install is actually a little easier with fewer steps, but on both you usually end up pulling the turbo.
Before we put the turbo back in we removed the stock wastegate and replaced it with a new one from BD Power. With the shorter rod on the new wastegate you get less push, so this is a great upgrade to keep it consistent. It comes pre-adjusted to allow 25 psi of boost pressure and we actually took it down a full turn to 24 psi, which is what the guys at Powerlabs recommended. With just these two upgrades, I have less lag and more boost, which of course is why I wanted to do it.