The 16G framed turbos should spool very quickly. If they don't there are a few possible reasons. One of the being the tune ofcourse, another is the routing of the intake tract, filter, IC, and piping.
I have a super short route for mine. It's not even a total length of 1 meter I think (3-ish feet). See picture: click
The piping does not have any hoses that can expand, just 2.5" steel piping, with couplers.
But as I mentined the tune makes a world of difference. I never achived this kind of response on a MAF and a E931 base code. It simply didn't want to go there.
And a very important thing that many racers forget to do is to go WOT. And by that I mean they go anything from 60-90 % throttle and consider it a WOT pull. It's simply not. You must stab it to 100% instantly. I know this sounds funny, we all go WOT right. I can say no in so many cases. Have had 100's of logs sent in to me where racers go WOT but only go to max 80-90% throttle. This reduces the VE drastically.