That mild steel intake pipe. Flakes of rust can't be good for compressor blades.
ATP Turbo sell plenty of T3 upgrades.
atpturbo.com
You might also find the parts you need from Kinugawa or Mamba on eBay.
What are the specs of your Nissan turbo? A "60/63" T3 was popular upgrade for Volvos back in the day.