Waste Gate Questions from a newb

[chevy6.5]

I'm new to diesels and really don't know much. I have a 6.5 turbo with vin "F" and it looks like there is a cat on it, but i read somewheres its actually the waste gate. Can anyone shed lite on this for me and explain what it does, and if it is possible to remove it for better exhaust flow. I was told that running 3" straight pipe would increase power and fuel mileage, any thoughts on this?

 

[chrisk1500]

The cat and WG are two different things....

Remove the cat and replace the downpipe for a better flowing exhaust....

 

[nitrohogg]

the waste gate is on the turbo, what looks like a cat down under would be a soot trap, I removed mine and noticed a big improvement.