I work for Holley
We have many NHRA racers running our Holley EFI system with great results. The software is very easy to use and most racers and engine builders can relate to the base fuel map that uses pounds per hour verses VE or Pulse Width.
If a tuner prefers they can opt to use VE tuning also.
We offer plug and play 24X or 58X harnesses for LS engines.
The software is available free online at
http://www.holley.com/TechService/Library.asp then choose V2 software installer. THere are several global folders in the software to get an idea of the cababilities of the system.
It has 2 gig of internat data logging.
Let me know if you have an questions regarding the Holley system.
Robin