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Autotap is just a logging scanner, its not going to increase performance.
LS1Edit will let you edit the tables in the PCM, and thus, you can increase your performance that way. I've used it, in conjuction with time on the dyno, and got power from it...but you need to know a little about what you are doing for sure.
For a novice, a pre-made tune is probably going to be your better option.