At what point does the stock 2g turbo throttle body become a restriction?

[calico]

At what point does the stock 2g turbo throttle body become a restriction? Is it good to say 300 rwhp and then should be changed? Is it really true the biggest benefit is throttle response and maybe a 2 or 3 horsepower gain? Very curious as i'm considering changing mine out when i do the upper intercooling piping.

 

[joe]

Or you can try a salvage yard.