Willie There is alot more to ECU's than most think. Different RPM ranges and most importantly match the ballast for max performance. The chrome ones are good for 10.5K with a .25 ballast give it a .8 ballast around 7k but you can drive it on the street then without burning up.
One day I will do a HOW TO on them with a overwhelming amount of testing information with matched and mis matched ballast resistors and ECU temps. Seriously alot of info.