To date the best dyno results on the Spec V have been with the AEM. The Injen is just slightly lower on dyno charts (but comes in that shiney crome piping). the hotshot intake has not dyno chart posted yet... COUGH... COUGH... NPM...myoung... COUGH... but i would suspect that it would be right there with the AEM.
Well, I personally like AEM, i don't know why. AEM is slightly more expensive than most of your listed products, besides Injen, but it has a lot of history behind it. I don't know much about the other intakes... but AEM sounds like a good one.