You can disagree all you like, but on the many 12 sec. cars I have done there was a .2ths improvement on actual track testing for each of the additions 3" DP and the IC Dut neck, so that was not opinion, but actual data.
Go back to an old copy of the GSXtra where we published the results of these changes on a stock GN at Bowling Green years ago which will verify my numbers with a stock turbo.
From your aggressive comments, I guess you may have done many GN's in this range, but my results and experience have shown stock injectors are NOT questionable at mid 12's, and have seen many 12 sec. GN's that have valve springs that are NOT toast, including my original 1987 turbo car.
I started my reply by stating an "opinion" which is based upon many, many turbo car builds , and I do understand there is more than one way to accomplish a goal, but it appears your voice is the only one that counts here?