Quote Originally Posted by Joe_Black
mbeach, please take a little time to review your research. You'll find the correct answers to many of the questions you brought up. I don't wish to get into any arguments or unpleasantness over readily available facts. Look into ECU's in general as a fundamental understanding of what they do and how they work will help you a great deal.
I appreciate your maturity and I do not want to begin an arguement as well. However, I did not just fall off the turnip truck. As near as I can tell, you are stating that a standalone user programmable ECU provides better driveability than a stock unit. This is just plain WRONG, and any tuner will tell you this. Driveability and convenience are tossed out the window when you are looking at replacing your factory ECU. You might be able to get *close* to the stock unit's reliability and adaptability, but you will always have some compromise.

The original poster wanted a quick boost in performance, not the headaches of hours of dyno time, potential replacement of the stock engine harness, and the high probability that a user-tunable unit will give the owner just enough control to blow up their motor.
In this case, a simple piggyback unit that modifies one or more of the factory sensor signals will do the job. Units on eBay alter the IAT sensor signal to trick the factory ECU, others advance timing, whatever. The point is that they are quick, cheap and reversible. Your car's ECU will protect itself should anything go way out of allowable parameters. -Thank you Limp Mode.

I challenge you to hook up a Haltech unit to a VX. We'll dyno before/after, and I GUARANTEE that you loose power across the board compared to the stock ECU. This is not a dig against the Haltech, this is any standalone unit. They have their applications, but this truck just ain't one of them.