Greatgab made a comment about knowing what your goals are, so I will ask: What are your goals?
>Do you want more power?
>Do you want a project that you can fiddle with?
I am going to assume that the $700 tune is from crateenginedepot, and is the GMPP tune. This is the one that was released by GM through its dealers and came with a factory warranty. That price includes the hardware, the software, and the installation.
The Trifecta (and others') "canned tune" works the same way that the GMPP tune works, except for providing more power at lower cost and not requiring the 3-bar sensors.
Neither of these require data logging or adjustment unless you have a car that is abnormal either through modification or some fault. Both are install-and-forget because the engines are consistent enough, and adaptable enough, that no after-install adjustments are necessary.
Beyond that are custom tunes that will cost more, take longer, and are more likely to cause problems, but are needed if you are heavily modified and desired if you want the ultimate in performance and are willing to deal with the potential problems.
Beyond bricking your ECM you should worry about destroying your engine. The LNF is not tolerant of some operating conditions and you can do serious damage if you don't know what you are doing and/or aren't paying attention.
Sky NA 2007 Midnight Blue
Sky RL 2008 Carbon Flash - Naked