Those Flows are holdin you back some. So is the stock IC.
I've yet to change my IC but lots of guys that went to a bigger inlet IC reported quicker spool up.
You don't know that. The age old ''flow masters chambers are not designed for turbo cars'' is obsolete. There are flowmasters that are pretty good now. Until we know which model he's running, we can't say that. Does the torque converter have anything to do with it? Yup. A 10" 3000 will be good. And the intake/outlet doesn't have that much to do with it? I think it does a little. You put a 4" maf pipe on there, with a good maf, and a 20 dollar manual boost controller, and a 3" DP with no cat, and a nice exhaust system, and you'll notice a difference I promise.
As far as the IC neck deal... I just replaced my stock IC with a dutt necked version, and got NOTHING. No quicker spool, no increase in boost, nothing.
I'm guessing it's like the whole 4" maf pipe, but with a 3.5" maf debate..
Ok, so the neck is bigger... well just 2 feet up the line, your throttle body is still the same diameter as it was before your dutt neck replacement.... so how does a
slightly bigger IC neck help spool up? I'm not seein' it....
I think it's a farce personally. All you did was let the air get stacked up to that restrictive throttle body 1 full second faster... If the throttle body never opened up, how's a slightly bigger ic neck gonna change anything. And what about the intercooler OUTlet? That's still the same diameter too...
At any rate. Do the converter, maf tube, downpipe and manual boost controller, and see what happens. I promise you you'll be impressed.
Though... what kind of headers are you running? And are you sure you don't have any exhaust leaks pre turbo?