This has been said many times, but I disagree that you don't need an elbow with the addition of mild injectors or boxes. This is based on tests that I and another member conducted - here is a description of each and the results: Installed 275HP injectors in a 99 2500 QC 4X4 5-speed 3. 54. 1500-3000rpm tests were done to compare results. Totally stock times averaged 12. 7 seconds (3 or 4 trials per average - I can't remember which). 275's only - times average 11. 7 seconds. 275's w/ elbow and boost module - 10. 5 seconds. Definite improvement even with the mildest of HP upgrades - as a matter of fact, more improvement with the addition of the 275's and elbow, than the 275's by themselves!
Now I agree that all the boost you can get (which is what most elbows give you) is sometimes too much, but an increase in air is needed with EVERY increase in fueling.
Also, if you install ONLY the elbow, with no Boost module, performance will decline b/c ECM will "see" additional boost (i. e. , over-boost) and cut fuel - tested this one while doing the above tests.