It may be the same size boat most people don't have a long run after the gate. If you can with out burning anything I would say unhook the gate from its dp and run it open and see if it still does it. Just one quick run. If it doesn't then you know you need a bigger pipe on it. You have to concider that your gate needs to exhaust anything the turbo doesn't need. And at bigger power it will need to flow more. Just like the exhaust of your turbo. My run is not that long but I used a 2" pipe vise a 1.5" pipe. After I did this I lost a pound of boost. Unless I hit the switch.

 

if you look at the first pic you can see the wastegate placement, it is right before the turbo after the two hot sides merge. There is a sharp 90 right after the wastegate so thats probably restricting it as well

 

Your coolant tank is stock but relocated, right? How did you secure it there? and would it fit there with A/C? I can see that you don't have A/C.

 

i just built a steel bracket to relocate the stock coolant tank. I do have a/c, i just had to bend a few lines a bit