Well I am looking to buy a programmer for my 1994 z28 but i cant find any dyno charts or hp gains. The two I was looking at was either a Hypertech Power Programmer III, or the hypertech Power Programmer Plus(which ones better???). Or what are some other ones that will get the most hp gain?

 

The "plus" is just an older model than the "III".... no significant difference. Neither of them is worthwhile for power gains... maybe explains why there are no published dyno tests. I've seen dyno tests where the Hypertech "power programming" actually reduced power. The Hypertech programmer is useful for changing gear ratios, adjusting the speed limiter, rev limter, shift point, fan on/off temps, etc. But its not worth the full price that they cost new. When buying a used one, you run the risk that the programmer has not been used to set the previous vehicle back to the stock tune, and it won't work on your car.

Best thing you can do is send your PCM to one of the "tuners" in the list of Supporting Vendors. They can net you at least 10HP on a totally stock engine, and more on a modified engine.