This is true, but to be fair to the OP, you CAN just buy the full bolt on kit from Vortech with the SST box and run it with just a tune. It's not the ideal set up but it will work fine.
The previous owner of my car did just that, and run it for 5 years without a problem and had a respectable 380hp.
However, for various reasons - safety, longevity and MORE POWER!!! I decided on various upgrades and supporting mods as most in the know would recommend. But its not cheap, so weigh up cost, power goals and reliability and make your decision.